Use of a composition comprising hydrogen peroxide in a cosmetic vehicle allows gentle discoloring of permanently colored, keratinous fibers which have been colored with a specific coloring composition. The coloring composition used for coloring the fibers comprises, in a cosmetic vehicle, a combination of at least one CH-acidic compound with at least one reactive carbonyl compound. The discoloring composition contains preferably between 0% and 15% by weight of hydrogen peroxide and has the effect, in particular in a working time of 5 to 20 minutes even without the use of organic peroxo compounds and in the absence of inorganic persalts, of effective color removal with simultaneous gentle treatment of the fibers.