Uses sandpaper on is a job description for the action of smoothing. Smoothing is the process of making a surface even and free from irregularities, such as roughness or bumps. It is often done with sandpaper, which is a type of paper coated with abrasive material, such as aluminum oxide, silicon carbide, or diamond dust. Sandpaper is used to smooth wood, metal, plastic, and other materials. It can also be used to remove paint, rust, and other surface imperfections.