A multi-component packaging unit (kit of parts) for reductively decoloring dyed keratin fibers, includes(I) a container (A) containing a cosmetic agent (a) and(II) a container (B) containing a cosmetic agent (b) and(III) a container (C) containing an aqueous, cosmetic agent (c)produced separately from each other, wherein agent (a) in container (A) includes a reductant (a1) as defined herein and agent (c) in container (C) includes (c1) one or more compounds of formula (I), A method for reductively decoloring dyed keratin fibers includes using the multi-component packaging unit.