Abstract: A rotary sweep scalper for cleaning grains deposited within a hopper. Grains to be processed are deposited through an upper inlet opening in the hopper and fall unto a screen located below. Those grains below a predetermined size pass through the screen to the hopper's lower discharge opening. A drive moves impeller arms located above the screen in the hopper to either force particles below a specified size through the screen or to discharge large particles through the hopper's side discharge opening. These movable impeller arms may be of different sizes and be spaced at different locations above the screen. Actual contact with the grain may be through a flexible flap attached to the lower edge of the impeller arms.