Sanding Sponge3M Advanced Abrasive Sanding Sponges are made with sharp, premium mineral; durable, flexible foam, and clog-resistant for long life. The sponge is comfortable to grip and maintains its shape through a variety of sanding jobs. Sanding is an integral step in preparing a surface to receive a coating. For the best sanding results, sand with the grain of the surface and work through a sequence of grits, from coarse to very fine, skipping no more than one grit between each sanding step. Use a coarse grit to remove light or heavy coatings. Use medium-grit sponge for moderate stripping or surface leveling in preparation for a coating. Use fine grit sponge for between coats of finish on freshly coated surfaces, such as wood and metal. Use it to scuff the finish in preparation for the next topcoat application.