A machine for dry cleaning coal. Raw coal is fed onto a perforated plate inclined at 12.5 degrees to 15 degrees to the horizontal. A pulsating air current is applied to the underside of the inclined plate, which stratifies the material, the coal forming the upper layer with the dirt below, which then passes into separate compartments. The Kirkup table gives a three-product separation; i.e., coal, middling, and reject.