Abstract: A conveyor system for a shredder, e.g. a shredder useful for comminuting yard and garden waste, includes a hopper for receiving the material to be shredded and a rotating hammer mill for shredding the debris into small pieces. Material is moved from the bin to the hammer mill using a lower conveyor and an inclined upper conveyor, which together form a nip in the vicinity of the inlet to the hammer mill section. In the present invention, clogs and interruption of shredding are prevented by automatic or selective reversal of the direction of movement of one of the conveyors for a predetermined amount of time. In the most preferred form of the invention, the lower conveyor is reversed in direction to cause the upper portion of a pile of debris to be moved toward the nip by the upper conveyor, while clogged material therebelow is moved away from the nip for a predetermined amount of time.