To keep sanpaper discs from curling up, make a simple jig to keep them flat. Cut out two pieces of 1/4-in. plywood that are slightly larger than the discs. Drill a 1/4-in. hole through the center of each of the pieces. Insert a bolt through one piece, lay the discs on it, and follow up with the second piece. Fasten the stack with a 1/4-in. bolt and wingnut.
While screwdrivers may look like pry bars, chisels, punches and scrapers, they should never be used for such purposes. A screwdriver is most effective when its blade is straight, balanced and sharp. Misusing yours will keep it from performing best when you need it to do what you bought it to do…drive screws. Also, be sure that the handle is clean and free of slippery oil or grease.