Sandpaper, also known as emery paper or abrasive paper, is used for sanding self-hardening clays, wood, metal, varnish or other materials. Abrasive grit is made from the mineral Corundum. Ideal for handicraft. Grit size, marked by the letter P, states the number of adhesive particles per cm2. Sandpapers with a lower P number are used for smoothing surfaces or sanding varnish, and the highest P numbers are used for polishing after applying the final layer of varnish to materials.