The 3M Aluminum Oxide Sandpaper is a general purpose abrasive that can be used on painted surfaces, bare wood, and metal. for the best sanding results, use this 3M sandpaper with the grain of the wood and work through a sequence of grits from coarse to very fine. These 9 in. x 11 in. medium-grit sandpaper sheets come in a pack of 5, and can be cut to size to use by hand, on a sanding block, or a power tool sander.