Cleaning and separation is the first processing step for harvested crops, removing foreign bodies such as earth, stones, sticks, weed seeds, and metal fragments before further handling. Equipment includes sieves, air aspirators that blow away light material, magnets for metal, and gravity tables that sort by density. The step protects downstream machinery from damage, removes contaminants that threaten food safety, and improves the uniformity of milling, malting, or packing. It is unglamorous but essential: a stone in grain can wreck a mill, and soil carries microbes. Good cleaning sets the quality baseline for everything that follows.