Sandpaper, often also known as glass paper, emery paper or abrasive paper, is used for sanding air-dry clay, wood, metal, varnish or other materials. The abrasive grains are made from the mineral corundum. Ideal for handicrafts. The grit, indicated by a number preceded by P, shows the number of abrasive grains per cm². Sandpapers with a lower number are ideal for, say, removing the original paint or smoothing out unevenness. Use papers with a higher P number to smooth the surface or to sand down varnish, and the highest P numbers for polishing after the final coat of varnish has been applied.