Iron, Rust, and Metal Deposits Removal Products and Methods of Use Thereof

Abstract

To provide a rust removal product that does not have a strong, unpleasant odor.SOLUTION: The present invention provides a composition for removing iron deposits, rust, or metallic particles from a surface, the composition including: at least one reducing agent; at least one chelating agent that changes color upon chelation; and at least one solvent.SELECTED DRAWING: None

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims priority to U.S. Provisional Application No. 63 / 526,764, filed on July 14, 2023.

Background Art

[0002] Rust - removing products remove iron deposits, small iron pieces, and / or rust adhering to surfaces such as automotive paint and clear coats. Current rust - removing products use thioglycolic acid, thiolactic acid, thiomalic acid, and their salts, esters, derivatives, such as sodium thioglycolate, ammonium thioglycolate, sodium mercaptoacetate, mercaptoacetic acid, etc. Thioglycolic acid reduces ferrous iron (Fe 3+ ) to ferric iron (Fe 2+ ) and chelates ferric ions to form ferric thioglycolate. This is a dark red / violet compound that can be clearly identified on vehicles. However, thioglycolates contain sulfur, and this sulfur gives the thioglycolic acid species a strong and unpleasant odor similar to that of rotten eggs. As a result, extremely foul odors and harmful gases are known characteristics associated with these iron - removing / iron - deposit - removing products.

[0003] There is a need in the art for rust - removing products that do not have a strong unpleasant odor, and the present disclosure meets this need.

Summary of the Invention

[0004] According to one aspect of the present disclosure, a composition for removing iron deposits, rust, or metal particles is provided, the composition comprising (a) at least one reducing agent, (b) at least one chelating agent whose color changes upon chelation, and (c) at least one solvent.

[0005] According to another aspect, a composition for removing iron deposits, rust, or metal particles from a surface is provided, This composition (a) water, (b) lactic acid, (c) 1,10-phenanthroline, (d) 2-butoxyethanol, (e) sodium metasilicate, (f) at least one preservative, (g) at least one thickener, and (h) at least one dye, and the composition has a pH of about 5 to about 7.

[0006] In one aspect, a method for removing iron, rust and / or metal particles from a surface is provided, This method (a) a step of applying the composition to the surface, the composition comprising: (i) at least one reducing agent, (ii) at least one iron chelating agent whose color changes by chelation, and (iii) at least one solvent, (b) a step of allowing the composition to stand on the surface for a certain period of time, wherein the reducing agent reduces metal, iron, or rust particles to form soluble iron species, and the iron chelating agent binds to the soluble iron species in the solution to form an iron chelate; and (c) a step of rinsing the composition and the soluble metal chelate from the surface, thereby removing rust, iron, and / or metal particles.

[0007] In some embodiments, the reducing agent includes strong acids, weak acids, mild reducing agents, or any combination thereof. In some embodiments, the reducing agent includes a compound selected from the group consisting of lactic acid, oxalic acid, hydroxylammonium hydrochloride, phosphoric acid, acetic acid, hydrochloric acid, sulfuric acid, citric acid, and any combination thereof.

[0008] In some embodiments, the chelating agent includes a heterocyclic organic compound whose color changes upon chelation. In some embodiments, the heterocyclic organic compound changes color to red upon chelation. In some embodiments, the heterocyclic organic compound changes color to pink upon chelation.

[0009] In some embodiments, the heterocyclic organic compound includes a substituted or unsubstituted phenanthroline, a substituted or unsubstituted bipyridine, or a derivative thereof. In some embodiments, the heterocyclic organic compound includes 1,10-phenanthroline, 2,2'-bipyridine, or a derivative thereof.

[0010] In some embodiments, the solvent includes a polar protic solvent or an aprotic polar solvent. In some embodiments, the solvent includes water, glycol ether, alcohol, acetone, or any combination thereof.

[0011] In some embodiments, the composition further includes at least one pH adjuster. In some embodiments, the pH adjuster includes an alkaline compound. In some embodiments, the alkaline compound is selected from the group consisting of sodium bicarbonate, potassium hydroxide, sodium metasilicate, and any combination thereof.

[0012] In some embodiments, the pH of the composition is from about 3 to about 7. In some embodiments, the pH of the composition is from about 5 to about 7. In some embodiments, the pH of the composition is from about 5 to about 6.

[0013] In some embodiments, the composition further includes at least one thickener. In some embodiments, the thickener includes a compound selected from the group consisting of hydroxyethyl cellulose (HEC) powder, hydroxypropyl methylcellulose (HPMC) powder, acrylic acid polymer, xanthan gum, and any combination thereof.

[0014] In some embodiments, the composition further comprises at least one surfactant. In some embodiments, the surfactant comprises an ionic surfactant, a non-ionic surfactant, an amphoteric surfactant, or any combination thereof. In some embodiments, the surfactant comprises a primary alcohol ethoxylate, a secondary alcohol ethoxylate, sodium lauryl sulfate, cocamidopropyl hydroxysultaine, or any combination thereof. In some embodiments, the surfactant comprises dodecylbenzene sulfonic acid.

[0015] In some embodiments, the composition further comprises at least one dye. In some embodiments, the dye changes the color of the composition without affecting the color change of the chelating agent due to chelation. In some embodiments, the dye changes the color of the composition to a color different from the color change of the chelating agent due to chelation.

[0016] In some embodiments, the composition further comprises at least one preservative. In some embodiments, the preservative comprises a biocide.

[0017] In some embodiments, any one of the compositions described herein does not contain a bad odor or a harmful odor (e.g., an unpleasant odor). In some embodiments, any one of the compositions described herein does not have a strong unpleasant pungent odor. In some embodiments, the bad odor or harmful odor is a "rotten egg" or sulfurous odor similar to hydrogen sulfide gas. In some embodiments, any one of the compositions described herein does not have an unpleasant mercaptan odor.

[0018] In some embodiments, the surfactant removes dirt, stain, or soil from the surface.

[0019] In some embodiments, the composition is applied to the surface using a spray bottle, a spraying device, or by wiping the composition onto the surface. In some embodiments, the surface is a metal surface. In some embodiments, the surface has a gel coat. In some embodiments, the surface is a clear coat. In some embodiments, the surface is the surface of an object selected from the group consisting of automobiles, motorcycles, tools, furniture, household appliances, utensils, cooking utensils, fabrics, carpets, concrete, ships, boats, watercraft, nuts and bolts, and glass substrates. In some embodiments, the surface is the outer or inner surface of an object.

[0020] In some embodiments, the composition is applied to a vertical surface. In some embodiments, the composition is applied to a horizontal surface. In some embodiments, the composition is applied to a surface that is not parallel to the floor.

[0021] In some embodiments, the certain period is from about 1 minute to about 1 hour.

[0022] Both the foregoing summary and the following detailed description are exemplary and explanatory. They are intended to provide further details of the present disclosure but are not to be construed as limiting. Other objectives, advantages, and novel features will be readily apparent to those skilled in the art from the following detailed description of the present disclosure.

Best Mode for Carrying Out the Invention

[0023] I. Summary Current rust removal compositions contain thioglycolic acid and its derivatives, which generate a strong, typical mercaptan-based, unpleasant and offensive odor that is difficult to mask and remove. Other names for thioglycolic acid include mercaptoacetic acid, thiobanic acid, thioglycolic acid, acetomercaptan, mercaptoacetic acid, 2-mercaptoacetic acid, 2-thioglycolic acid, and thioglycolic acid. The unpleasant mercaptan odor is distinctively characterized by a combination of sulfur and acidic odors, as well as putrid and burnt or burning-like odors. Thioglycolic acid can decompose into other compounds such as hydrogen sulfide (H2S) and light mercaptans that are highly malodorous. See U.S. Patent Application No. 2022 / 0054379.

[0024] This odor is unpleasant when using compositions containing thioglycolic acid and its derivatives and is a significant drawback in its use, especially in the field of rust removal. To counter this unpleasant odor, manufacturers have employed many strategies such as using odor masking agents to mask the odor of thioglycolic acid or reducing the release of H2S and / or light mercaptans that may cause the odor.

[0025] Examples of conventional strategies for dealing with the harmful odors associated with thioglycolic acid compositions include the use of natural substances, natural substance extracts, or fragrance-based type odor masking agents, adsorbents such as charcoal, zeolite, or cyclodextrin that enable the reduction of the amount of H2S and / or light mercaptans released, and the use of certain additives such as polyphenols and metal oxides that enable the reduction of the amount of H2S and light mercaptans released. None of these solutions are ideal.

[0026] In the automotive field in particular, dealing with iron powder is crucial. Iron particles are often embedded in the coatings (such as wheels and body panels) that coat automobiles, and if left untreated, they can cause rust and other forms of corrosion. Dissolving and removing these particles helps prevent damage to the vehicle's paint and protects its appearance. Iron particles can originate from various sources, such as brake dust, industrial fallout, and road debris. When these particles come into contact with the vehicle's surface, they can bond to the paint and form unsightly rust stains.

[0027] In the context of vehicle details, Fe2O3 (iron(III) oxide) may often refer to iron particles deposited on the vehicle's surface as a result of brake dust or other sources of floating iron particles. If these iron particles are not removed in a timely manner, they can cause stains and discoloration on the vehicle's paint, wheels, and other surfaces. Removing the iron particles can prevent damage to the vehicle's paint and finish.

[0028] The present invention is directed to compositions and methods for removing iron deposits, rust, or metal particles from surfaces including, but not limited to, the surfaces of automobiles. The compositions described herein do not have the unpleasant odor found in current thioglycolic acid-based formulations. The rust-removing compositions of the present invention use at least a reducing agent that reduces ferric iron to soluble ferrous iron so that it can be removed from the surface, and at least one chelating agent that chelates iron. The chelating agent used herein changes color when it chelates iron, indicating that the rust-removing composition is functioning.

[0029] The use of a rust or iron particle-removing composition that does not emit an unpleasant mercaptan odor has significant advantages over prior art thioglycolic acid-based formulations. For example, the use of thioglycolic acid-based formulations may require significant ventilation and / or respiratory protection, which is not necessary for the compositions described herein. By separating the iron chelating agent from the iron reducing agent, a specific color change can also be achieved.

[0030] II.Composition The rust or iron particle removal composition described in this specification (a) at least one reducing agent, (b) at least one chelating agent whose color changes upon chelation, and (c) contains at least one solvent. While not wishing to limit the present invention to any theory or mechanism, the reducing agent in the composition reduces iron oxide to soluble iron species, and a color change is observed due to chelation by the chelating agent, indicating that the product is functioning as intended.

[0031] In some embodiments, the composition contains from about 1 wt% to about 50 wt% of a reducing agent. In some embodiments, the composition contains from about 5 wt% to about 45 wt% of a reducing agent. In some embodiments, the composition contains from about 10 wt% to about 40 wt% of a reducing agent. In some embodiments, the composition contains from about 10 wt% to about 30 wt% of a reducing agent. In some embodiments, the composition contains from about 15 wt% to about 25 wt% of a reducing agent.

[0032] In some embodiments, the composition contains about 1 wt%, about 5 wt%, about 10 wt%, about 15 wt%, about 20 wt%, about 25 wt%, about 30 wt%, about 35 wt%, about 40 wt%, about 45 wt%, or about 50 wt% of a reducing agent. In some embodiments, the composition contains about 20 wt% of a reducing agent.

[0033] In some embodiments, the composition comprises from about 0.01 wt% to about 5 wt% chelating agent. In some embodiments, the composition comprises from about 0.1 wt% to about 5 wt% chelating agent. In some embodiments, the composition comprises from about 0.1 wt% to about 4 wt% chelating agent. In some embodiments, the composition comprises from about 0.1 wt% to about 3 wt% chelating agent. In some embodiments, the composition comprises from about 0.1 wt% to about 2 wt% chelating agent. In some embodiments, the composition comprises from about 0.1 wt% to about 2 wt% chelating agent. In some embodiments, the composition comprises from about 0.1 wt% to about 0.5 wt% chelating agent.

[0034] In some embodiments, the composition comprises about 0.01 wt%, about 0.1 wt%, about 0.25 wt%, about 0.5 wt%, about 1 wt%, about 2 wt%, about 3 wt%, about 4 wt%, or about 5 wt% chelating agent. In some embodiments, the composition comprises about 0.25 wt% chelating agent.

[0035] In some embodiments, the composition further comprises a surfactant and a solvent to provide detergency for removing dirt and stains from the surface. In some embodiments, the surfactant comprises an ionic surfactant, a nonionic surfactant, an amphoteric surfactant, or any combination thereof. In some embodiments, the ionic surfactant comprises a cationic surfactant and / or an anionic surfactant. In some embodiments, the surfactant comprises a primary alcohol ethoxylate, a secondary alcohol ethoxylate, sodium lauryl sulfate, cocamidopropyl hydroxysultaine, or any combination thereof. In some embodiments, the surfactant comprises dodecylbenzenesulfonic acid.

[0036] In some embodiments, the solvent includes a polar protic solvent or an aprotic polar solvent. In some embodiments, the solvent includes water, glycol ether, alcohol, acetone, or any combination thereof. In some embodiments, the solvent includes water. In some embodiments, the solvent includes 2-butoxyethanol. In some embodiments, the solvent includes water and 2-butoxyethanol.

[0037] In some embodiments, the reducing agent includes a strong acid, a weak acid, a mild reducing agent, or any combination thereof. Suitable reducing agents that can be used in the compositions described herein include, but are not limited to, lactic acid, oxalic acid, hydroxylammonium chloride, phosphoric acid, acetic acid, hydrochloric acid, sulfuric acid, citric acid, and any combination thereof. In some embodiments, the reducing agent is lactic acid. One advantage of using lactic acid in the compositions of the present invention is that it is less toxic and less dangerous than thioglycolic acid.

[0038] In some embodiments, the chelating agent includes a heterocyclic organic compound. In some embodiments, the chelating agent acts as an indicator indicating that the product is removing iron deposits, rust, or metal particles. The heterocyclic organic compound may change color to red by chelation. The heterocyclic organic compound may change color to pink by chelation.

[0039] In some embodiments, the heterocyclic organic compound includes a substituted or unsubstituted phenanthroline, a substituted or unsubstituted bipyridine, or a derivative thereof. As used herein, "substituted" or "derivative thereof" may refer to a compound containing one or more alkyl, alkenyl, alkynyl, cycloalkyl, aryl, halo, hydroxyl, oxy, alkoxy, amino, ester, or carboxyl substituents. In some embodiments, the heterocyclic organic compound is 1,10-phenanthroline.

[0040] In some embodiments, the composition further comprises at least one dye. Dyes suitable for use in the composition are inert and do not interact or react with any of the components of the composition. In some embodiments, the dye changes the color of the composition without affecting the color change of the chelating agent by chelation. In some embodiments, the dye changes the color of the composition to a color different from the color change of the chelating agent by chelation. In some embodiments, the dye is a blue dye or a turquoise dye. Examples of dyes suitable for use in the composition include, but are not limited to, FD&C Blue No.1, FD&C Blue No.2, FD&C Blue No.4, Acid Blue 1, and Orcoterge Turquoise DG-ST.

[0041] In some embodiments, the pH of the composition is from about 3 to about 7, in some embodiments, the pH of the composition is from about 5 to about 7, in some embodiments, the pH of the composition is from about 5 to about 6, and in some embodiments, the pH of the composition is about 3, about 4, about 5, about 6, or about 7.

[0042] To adjust the pH, at least one pH adjuster can be used. In some embodiments, the pH adjuster comprises an alkaline compound. Examples of alkaline compounds suitable for use in the composition include, but are not limited to, sodium bicarbonate, potassium hydroxide, sodium metasilicate, and any combination thereof. In some embodiments, the pH adjuster comprises sodium metasilicate.

[0043] Furthermore, the viscosity of the composition can be adjusted to improve the adhesiveness or adherence of the composition to the surface and prevent excessive outflow of the sprayed or applied product. Any thickener suitable for a weakly acidic solution can be used, for example, hydroxyethyl cellulose (HEC) powder, hydroxypropyl methylcellulose (HPMC) powder, acrylic acid polymer, xanthan gum, and any combination thereof.

[0044] In some embodiments, the composition further comprises a preservative. In some embodiments, the preservative is a biocide. Suitable preservatives include, but are not limited to, sodium benzoate, potassium sorbate, DMDM hydantoin, methylisothiazolinone, Kathon-LX 1.5, Nuosept 95, diazolidinyl urea, and parabens.

[0045] In some embodiments, the composition (a) water, (b) lactic acid, (c) 1,10-phenanthroline, (d) 2-butoxyethanol, (e) sodium metasilicate (f) at least one preservative, (g) at least one thickener, and (h) at least one dye. Furthermore, the composition can have a pH of about 5 to about 7.

[0046] The composition of the present invention does not exhibit a strong, unpleasant, pungent mercaptan odor that is present in current rust removal compositions. In some embodiments, the composition is free of malodors or noxious odors. In some embodiments, the composition does not emit odors that can irritate the nose and / or throat, such as the odor of "rotten eggs", mercaptan odor, or sulfur odor. In some embodiments, the composition does not contain thioglycolic acid or its salts. In some embodiments, the composition contains less than about 0.005 ppm, less than about 0.004 ppm, less than about 0.003 ppm, less than about 0.002 ppm, less than about 0.001 ppm, or less than about 0.0005 ppm of mercaptan.

[0047] III. Method To produce the composition, the components are mixed and it is confirmed that all solids have dissolved.

[0048] The compositions described herein are used to remove iron, rust and / or metal particles from a surface. In some embodiments, a method for removing iron, rust and / or metal particles from a surface comprises: (a) applying any one of the compositions described herein to the surface; (b) allowing the mixture to stand on the surface for a period of time, wherein the reducing agent reduces metal, iron, or rust particles to form soluble iron species, and the chelating agent binds to the soluble iron species in solution to form an iron chelate; and (c) rinsing or removing the mixture and the iron chelate from the surface, thereby removing rust, iron, and / or metal particles from the surface.

[0049] The composition can be applied to the surface in a variety of ways, including but not limited to spraying using a trigger bottle or spray device, or brushing, rolling, or wiping onto the surface.

[0050] In some embodiments, the surface is cloth, concrete, marble, other types of stone and masonry, plastic, copper, iron, rubber, aluminum, steel, brick, stucco, chrome, metal, porcelain, fiberglass, colorfast cloth, carpet, or an iron-containing surface. The surface can be the surface of an object selected from the group consisting of automobiles, motorcycles, tools, furniture, household appliances, utensils, cooking appliances, fabrics, carpets, concrete, ships, boats, watercraft, nuts & bolts, glass substrates, automotive metal parts, household metal parts, industrial metal parts, tractors, antiques, agricultural implements & appliances, trailers and hitches, marine applications, purification systems and piping, and household surfaces. In some embodiments, the surface is a metal surface. In some embodiments, the surface has a gel coat. In some embodiments, the surface is a clear coat. In some embodiments, the surface is the outer or inner surface of an object. In some embodiments, the surface is an automobile.

[0051] In some embodiments, the composition is left on the surface for a fixed period of from about 1 minute to about 1 hour. In some embodiments, the composition is left on the surface for about 1 minute, about 5 minutes, about 10 minutes, about 15 minutes, about 20 minutes, about 30 minutes, about 40 minutes, about 50 minutes, or about 60 minutes.

[0052] IV. Definition As used herein, "about" is understood by those skilled in the art and varies somewhat depending on the context in which it is used. When there is use of a term that is not clear to those skilled in the art, considering the context in which it is used, "about" means plus or minus 10% of the particular term.

[0053] The use of the terms "a", "an", and "the" and similar reference words in the context of describing elements (especially in the context of the following claims) are to be construed to cover both the singular and plural forms, unless the context clearly dictates otherwise or there is a clear contradiction in the context. The description of a range of values herein is, unless otherwise stated herein, merely intended to serve as a shorthand reference to each individual value falling within the range, and each individual value is incorporated herein as if it were individually described herein. All methods described herein can be performed in any suitable order, unless otherwise stated herein or the context clearly dictates otherwise. The use of any examples provided herein, or of exemplary language (e.g., "such as") is merely intended to better illustrate embodiments and is not intended to limit the claims unless otherwise stated. No language in this specification should be construed as indicating any non-claimed element as essential.

[0054] Various embodiments will be described below. It should be noted that the specific embodiments are not intended as an exhaustive description or as a limitation to the broad aspects discussed herein. One aspect described in conjunction with a particular embodiment is not necessarily limited to that embodiment and can be practiced in conjunction with any other embodiment.

[0055] The invention as generally described above will be more readily understood by reference to the following examples, which are provided by way of illustration and are not intended to limit the invention.

Examples

[0056] Although specific embodiments have been illustrated and described, it is to be understood that changes and modifications can be made therein in accordance with the ordinary skills of those in the art without departing from the broader aspects of the technology as defined in the following claims.

[0057] Example 1 One embodiment of the rust-removing composition contains 50 to 70% by weight of water, 15 to 20% by weight of lactic acid, 0.01 to 0.5% by weight of 1,10-phenanthroline, 1 to 5% by weight of linear alcohol ethoxylate, 1 to 5% by weight of sodium lauryl sulfate, 1 to 5% by weight of dodecylbenzenesulfonic acid, 1 to 5% by weight of Mackam CBS 50G, 1 to 5% by weight of glycol ether DB, 0.001 to 0.1% by weight of hydroxypropyl methylcellulose, 0.001 to 0.1% by weight of sodium metasilicate, 0.001 to 0.1% by weight of Nuosept 95, and 0.0001 to 0.1% by weight of Orcoterge Turquoise DG-ST.

[0058] Example 2 The rust-removing composition of Example 1 may be used to remove rust from the surface of an automobile. This composition is sprayed onto the surface of the automobile and left for about 1 hour. During this time, lactic acid reduces iron(III) in the rust to iron(II), and 1,10-phenanthroline binds to iron(II) to form an iron chelate. A color change occurs during this time, indicating that 1,10-phenanthroline has bound to iron(II) to form a red compound. After 1 hour, the composition is rinsed from the automobile surface, and there is no foul or unpleasant odor from the composition.

[0059] The embodiments exemplified in this specification can also be suitably implemented with respect to any element or elements, limitation or limitations not specifically disclosed herein. Therefore, for example, terms such as "comprising", "including", "containing", etc. shall be construed in an expansive manner without limitation. Furthermore, the terms and expressions employed in this specification are used as terms of description and are not meant to be limiting. The use of such terms and expressions is not intended to exclude equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the claimed technology. Further, the expression "consisting essentially of" is understood to include the specifically recited elements and additional elements that do not substantially affect the basic and novel characteristics of the claimed technology. The expression "consisting of" excludes elements not specified.

[0060] This disclosure is not limited from the perspective of the specific embodiments described in this application. As will be apparent to those skilled in the art, many modifications and variations can be made without departing from its spirit and scope. In addition to those listed herein, functionally equivalent methods and compositions within the scope of this disclosure will be apparent to those skilled in the art from the foregoing description. Such changes and variations are intended to be included within the scope of the appended claims. This disclosure is limited only by the terms of the appended claims and such claims are limited along with the full scope of equivalents to which such claims are entitled. It should be understood that this disclosure is not limited to a particular method, reagent, compound, or composition and can, of course, vary. Also, it should be understood that the terms used in this specification are for the purpose of describing particular embodiments only and are not intended to be limiting.

[0061] In addition, when a feature or aspect of the present disclosure is described in terms of a Markush group, one of ordinary skill in the art will recognize that the present disclosure is thereby also described in terms of any individual member of the Markush group or a subgroup of members.

[0062] As will be understood by one of ordinary skill in the art, for any purpose, particularly for the purpose of providing a written description, all ranges disclosed herein include any and all possible subranges and combinations of those subranges. It can be readily recognized that any recited range can be fully described and enabled such that the same range is broken down into at least equal halves, thirds, quarters, fifths, tenths, etc. As a non-limiting example, each range discussed herein can be readily broken down into lower thirds, middle thirds, and upper thirds, etc. Also, as will be understood by one of ordinary skill in the art, all expressions such as "up to," "at least," "greater than," "less than," etc. include the recited number and refer to ranges that can be subsequently broken down into subranges as described above. Finally, as will be understood by one of ordinary skill in the art, ranges are composed of individual members.

[0063] All publications, patent applications, issued patents, and other documents referred to herein are incorporated herein by reference as if each individual publication, patent application, issued patent, or other document were specifically and individually indicated to be incorporated by reference. Definitions contained in incorporated documents are excluded to the extent they contradict the definitions of the present disclosure.

[0064] Other embodiments are described in the following claims.

Claims

1. A composition for removing iron deposits, rust, or metal particles, comprising: (a) water, (b) lactic acid, (c) 1,10-phenanthroline, (d) 2-butoxyethanol, (e) sodium metasilicate, (f) at least one preservative, and (g) at least one thickener, and having a pH of 5 to 7.

2. The composition according to claim 1, further comprising (h) at least one dye.

3. The composition according to claim 1, wherein the at least one thickener is selected from the group consisting of hydroxyethyl cellulose (HEC) powder, hydroxypropyl methyl cellulose (HPMC) powder, acrylic acid polymer, xanthan gum, and any combination thereof.

4. The composition according to claim 1, further comprising at least one surfactant selected from the group consisting of primary alcohol ethoxylate, secondary alcohol ethoxylate, dodecylbenzenesulfonic acid, cocamidopropyl hydroxysultaine, and any combination thereof.

5. A method for removing iron, rust and / or metal particles from a surface, the method comprising: (a) applying a composition to the surface, the composition comprising: (i) lactic acid (ii) at least one chelating agent whose color changes by chelation, (iii) at least one solvent, and (b) allowing the composition to stand on the surface for a period of time, wherein a reducing agent reduces metal, iron, or rust particles to form soluble iron species, and the chelating agent binds to the soluble iron species in the solution to form an iron chelate; and (c) rinsing the composition and the iron chelate from the surface, thereby removing rust, iron, and / or metal particles from the surface. The composition further comprises: (iv) at least one thickener (v) at least one surfactant, and (vi) at least one preservative.

6. The method according to claim 5, wherein the thickener is selected from the group consisting of hydroxyethyl cellulose (HEC) powder, hydroxypropyl methyl cellulose (HPMC) powder, acrylic acid polymer, xanthan gum, and any combination thereof.

7. The method according to claim 5, wherein the surfactant removes scale, dirt, or soil from the surface.

8. ​ ​ The method according to claim 5, wherein the at least one surfactant is selected from the group consisting of primary alcohol ethoxylate, secondary alcohol ethoxylate, dodecylbenzene sulfonic acid, and any combination thereof.

9. A method for removing iron, rust and / or metal particles from a surface, the method comprising: (a) applying a composition to the surface, the composition comprising: (i) lactic acid (ii) at least one chelating agent whose color changes upon chelation, (iii) at least one solvent, and (b) allowing the composition to stand on the surface for a period of time, wherein a reducing agent reduces metal, iron, or rust particles to form soluble iron species, and the chelating agent binds to the soluble iron species in solution to form an iron chelate, and (c) rinsing the composition and the iron chelate from the surface, thereby removing rust, iron, and / or metal particles from the surface. The composition has a pH of 5 to 7.