Sometimes you need to cut a sheet of sandpaper into smaller parts — like into quarters — for easier hand sanding. But don't cut the sheet with scissors; the abrasive face will dull the scissors' cutting edge. Instead, turn it over and lightly score the back side with a utility knife or a straight-edge. Don't cut clear through, however, because it'll dull your utility knife blade, too. Bend the paper backing back and forth on the score, and then tear it apart by hand. To make hand sanding easier still, with the back side down, pull it back and forth over a sharp edge. That'll get rid of stiffness, and soften things up.