Natural and synthetic materials in fine granular form incorporated in buffing compounds and attached to cloth or paper. Abrasives are generally used in grades of coarse to fine and may be identified by a numerical system. Abrasive materials are either in loose form or formed together into wheels, files or bricks or adhered to cloth or paper with resin or glue. Natural abrasives include sand, baking soda, garnet, emery and flint. Metallic shot, grit and plastic material are also used as abrasives in cleanings of castings and surface preparation.