Shop for Paint at The Home Depot. 3M Sanding Sponges are designed for wet or dry sanding on wood, paint, metal, plastic or drywall. Use this medium-grit sponge for moderate stripping or surface leveling in preparation for a coating. This sponge features conventional 3M abrasives and is made with durable, flexible foam. The block shape makes it easy to hold and sands flat, contoured, or irregular surfaces. 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. 3M sanding sponges are available in medium, fine and extra fine grits.