Q: Why are there so many types of wire brushes? —Christelle Laprade, Jersey City, N.J.
A: As you can see from the wheel-style wire brushes on this brush-and-blade "tree," they do come in a variety of diameters and widths—with fine, coarse, straight, crimped, or twisted bristles made of regular steel, stainless steel, bronze, and brass—each one suited to a particular metal-cleaning task. For example, to remove rust from steel, a 4-inch wire wheel that fits in a drill and has aggressive, crimped-steel bristles is a good all-around choice. (Brushes 6 inches or more in diameter are intended for bench grinders.) But on aluminum, stainless-steel bristles are better because they won't leave black carbon deposits. Softer brass or bronze brushes won't spark or scratch steel. If you aren't sure which brush to pick, a good rule of thumb is to start coarse and go finer as the job demands it.