Different types of sandpaper are used for different tasks. Generally speaking, the finer the grit or number (i.e., 60 or above), the smoother and more even the surface. Sanding with very fine sandpaper, such as 220 grit, is recommended. Use 100-grit sandpaper and higher for staining and extra-fine sandpaper with a grain of 360 to 400 to finish surfaces smoothly.