The main reason the wire cup brush is black is the oxidation of the steel surface and air. My recommendation is to soak the wire rope cup brush in hydrogen peroxide or 84 disinfectant for 10 minutes before using the wire rope. The oxide is then sucked away and rinsed, so it can be used right away.Wire cup brush, generally made of galvanized steel wire, with the oxidation of galvanized layer, wire cup brush from white bright color gradually dark, until green red. As long as the galvanized layer is thick, discoloration will be delayed and the life of the wire cup brush will be extended. There does not appear to be a stainless steel wire cup brush. Wire Burhs are widely used, manganese phosphorescent coated wire rope and wire rope are steel wire products.