Here’s how to make your own reusable sanding blocks. Cut six blocks from scrap 3/4-in.plywood for each sandpaper grit you commonly use. Make them 2-1/2 in. x 4-3/4 in. Spray adhesive on both a square of cork tile and each block. Stick a block to the cork and cut the cork flush with a utility knife. Then spray adhesive on a sheet of sandpaper and stick it on each block cork side down as shown. Cut the sandpaper flush with the cork, and label each block.