Mustard cleaning machine for seed processing, used to clean mustard seed by sieving out dust and other foreign matter. Seed is fed through a funnel-shaped top hopper onto stacked sieve screens with mesh decks, and the cleaned seed and separated fractions leave through angled outlet chutes. An electric motor on the base frame drives the screens through a belt and a large pulley. The open steel frame is finished in pale green-white, with a teal hopper, side straps and trim.