Grain cleaning after harvest is important as it removes unwanted materials from the grain. Clean grain has a higher value than grain that is contaminated with straws, chaff, weed seeds, soil, rubbish, and other non-grain materials. Grain cleaning will improve the storability of grain, reduce dockage at time of milling, and improve milling output and quality. Seed cleaning will reduce damage by disease, and improve yields. Following are some general guidelines for cleaning grain and seed.