Abstract: A multi-chambered scrubber is employed to thoroughly wash gravels or materials bearing heavy precious metals. The apparatus includes a multi-chambered scrubber drum which is supported at an angle by a frame and adapted to be driven by a variable speed drive system. The scrubber drum includes at least two sections each of which has a polygonal shaped, water-tight interior chamber. Each of the sections is separated by a retainer ring having an opening therein smaller in area than the area of the next preceeding scrubber chamber. The scrubber sections are interchangeable and may be connected one to the other in any of a variety of combinations as may be dictated by the material being scrubbed. The polygonal shape of the scrubber chambers contributes to a greatly improved washing and disintegrating action on the material being treated. The scrubber apparatus also includes a plurality of removable wear plates which can be replaced as they become worn down and damaged.