A method for cleaning surfaces using aminoplast foam pieces produced from (a) open-cell aminoplast foams having a density in the range from 5 to 500 kg/m.sup.3 and a mean pore diameter in the range from 1 .mu.m to 1 mm or (b) open-cell aminoplast foams having a density in the range from 5 to 500 kg/m.sup.3 and a mean pore diameter in the range from 1 .mu.m to 1 mm, which have been treated (b1) with an aqueous formulation of at least one compound (b-1) having at least one hemiaminal or aminal group per molecule or at least one copolymer which comprises, incorporated in the form of polymerized units, at least one comonomer containing OH groups or .beta.-dicarbonyl groups or epoxide groups, or (b2) with at least one polymer (c-1) which is solid at room temperature, contains carboxyl groups and/or carboxylic ester groups and has a molecular weight M.sub.n in the range from 1000 to 1 000 000 g/mol,the aminoplast foam pieces used having an average diameter in the range from 0.1 mm to 50 mm.