The aftertreatment and dye liquors can also contain conventional auxiliaries, suitably electrolytes such as salts, for example sodium sulfate, ammonium sulfate, sodium or ammonium phosphates or polyphosphates, ammonium acetate or sodium acetate and/or acids such as mineral acids, for example sulfuric acid or phosphoric acid, or organic acids, preferably lower aliphatic carboxylic acids such as for