To a cold solution containing 1 per cent. of bromine, 1 per cent. of caustic soda at 36° B. is added, then the material, to be bleached is first wet and then immersed in this bath until completely decolorized. It is passed into a newly-acidulated bath, rinsed, and dried. After the bromine bath has been used up, it is regenerated by adding 1 per cent. of sulphuric acid, which liberates the bromine. To the same bath caustic soda is added, which regenerates the hypobromite of soda. The hydrofluosilicic acid can be used, instead of the sulphuric acid, with greater advantage. A bath used up can also be regenerated by means of the electric current.