The invention pertains to an aqueous composition having a pH of 3 or less and comprising the following ingredients, based on the total weight of the composition: a) 0.05-40 wt % of a polymeric thickener having --COOR groups, wherein R is independently chosen from H, OH, and a carbon-containing group, and b) 0.05-60 wt % of hydrogen peroxide, wherein the active oxygen content attributable to ingredient a) is at least 0.02 wt %, based on the total weight of the composition, with the proviso that (co)polymers prepared from (meth)acrylate monomers are absent.