Knot brushes are used for high intensity aggressive brushing. Knot brushes absorb the vibrations from cutting and bending that normally cause intense wire fatigue. Standard sized brushes are used for uniform heavy brushing, stringer bead brushes are used for cleaning small channels in order to prepare for welding or cleaning cracks in asphalt and concrete.

Scratch brushes provide the same function as knot brushes, but they aren't powered by a drill. They're best used for removing paint or rust from a surface.