A multi-part kit system comprising a solid part A which comprises at least one acetyl donor, a liquid part B in the form of an aqueous composition which comprises 3 to 35 wt. % of hydrogen peroxide and one or more parts C, wherein the solid part A and/or the part(s) C comprise at least one surfactant selected from the group consisting of anionic surfactants, amphoteric surfactants and nonionic surfactants, wherein the composition of the parts of the multi-part kit system is such, that directly after being mixed with each other and water in a specified ratio the pH of the mixture is in the range of 5.5 to 8.
