Accelerator solution suitable for forming a redox system with peroxides and having a high storage stability, consisting essentially of (a) more than 1.0 wt % of one or more reducing agents, at least one of them being selected from ascorbic acid and sodium formaldehyde sulphoxylate, (b) one or more metal salts, at least one of them being selected from the group consisting of transition metal salts, lithium salts, and magnesium salts, (c) one or more organic oxygen-containing solvents, (d) optionally one or more stabilisers, and (e) optionally water.