The term 'USE SANDPAPER' can be broken down into two crossword solutions: ABRADE (6 letters) and COARSEN (7 letters). Sandpaper is a material made of paper or cloth with an abrasive surface, usually used for smoothing or polishing surfaces. ABRADE means to wear away or rub off the surface of something by friction or erosion. COARSEN means to make or become rough or harsh. Therefore, the term 'USE SANDPAPER' can be interpreted as using sandpaper to wear away or rub off the surface of something, or to make it rough or harsh.