Elmer's Glue on Canvas, then paint the whole thing. I have totally done this, but with a hot glue gun. Elmer's Glue seems to be a better idea since hot glue leaves behind strings and is harder to work with.
Use those old music makers to make adorable animal crafts like the CD Mouse. Recycled crafts are fun ways to help the environment and get rid of clutter. Plus, these fun little mice are perfect preschool decorations because they're cute.