Multi-component package unit (kit-of-parts), ready-to-use agent, and methods for reductive decolorizing of dyed keratinous fibers are provided herein. In an embodiment, a multi-component package unit includes, separately packaged, a first container (A), a second container (B), and a third container (C). The first container (A) includes a cosmetic agent (a) that includes (a1) one or multiple reducing agents chosen from the group of formamidine sulfinic acid, sodium dithionite, zinc dithionite, potassium dithionite, hydroxymethanesulfinic acid, aminomethanesulfinic acid, cysteine, thiolactic acid, sulphanylacetic acid (thioglycolic acid) and/or ascorbic acid. The second container (B) includes a cosmetic agent (b) that includes one or multiple oxidizing agents. The third container (C) includes a cosmetic agent (c) that includes (c1) one or multiple alkalizing agents. The weight ratio of the total amount of all reducing agents (a1) to the total amount of all oxidants (b1) has a value from about 50.0 to about 4.0.
