Abstract: A washing machine for nondestructively cleaning machine parts comprises an enclosure and a water wheel for projecting a wash liquid against an object to be treated. The water wheel rotates at high speed. Washing liquid is fed into a central opening in the water wheel, and the liquid is projected at high velocity against the object to be cleaned. The liquid is projected in a pattern comprising a plurality of spaced-apart, geometrically similar, arcuate, dense zones of wash liquid. A pulsed cleaning effect is obtained. The device is especially useful for cleaning worn automotive and truck brake shoes prior to reconditioning the brake shoes.