Sanding in tight corners.
On almost any car there will be some very tight corners that need sanding when doing your paint prep. I made this little tool for getting into those corners. It's a length of 1/8 x 1" steel, bent slightly, handle wrapped in closed cell upholstery foam, and a piece of stick-on sandpaper attached to the business end (photo 1). Photo 2 shows the tool's use in a tight corner of my pickup bed.