If you wear contacts, you know how easy it can be to end up with many more cases than you need. Every time you buy solution or get an eye exam, you get another.
Find a scrap piece of wood or plastic of a convenient size and arrange your cases on it.
Turn them over and put a dab of hot glue on each side, then put back in place on the board.
When all your cases are glued on, fill with components, buttons, beads, or what-have-you. Label the caps with a permanent marker. And that’s it! Your parts are safe and sound, easy to get to and organized.