Brush Hero BH107 Replacement Brushes, Pair (Stiff- White/White) Replacement brushes for the Brush-Hero system. White = Stiff/Hard Bristles. Use on tougher jobs like wheels, rims and motors. Do NOT use on paint! Black = Soft Bristles. Use on fine finishes such as chrome or paint. Blue (Grimefighter) = Stiffest Bristles. Use on the toughest jobs, such as scum on your boat's waterline, house siding, pool tiles, and rain gutters. Do NOT use on paint or chrome!