There is a strong need for a detergent composition that can easily and efficiently remove modified oil stains that have been altered and polymerized by the action of heat,
sunlight, indoor light,
oxygen, etc. [Solution] (a) Component: A glycol monoalkyl
ether solvent having oxyalkylene groups having 2 and / or 3 carbon atoms, wherein the
solvent has a LogP of less than 0 (component (a-1)) and the
solvent has a LogP of 0 or more and 1.5 or less (component (a-2)), in a total amount of 1% by
mass or more and 15% by
mass or less. (b) Components:
Alkanolamine in an amount of 0.5% by
mass or more and 10% by mass or less And, including water, The
mass ratio of component (a-1) to component (a-2), [(mass of component (a-1)] / [(mass of component (a-2)], is between 0.05 and 10. A
cleaning agent composition for hard surfaces, having a pH of 8 to 13 at 25°C, is used and applied to modified oil stains on the hard surface for cleaning.