Hmmm. I mostly use grey for piecing so I have one little section in a drawer where I keep all my grey filled bobbins. For the ones that I really want to be sure the bobbin matches the top thread, I just put the bobbin and the spool in a little ziplock sandwich bag and toss it into the drawer. I've never been successful at finding the hair elastics that everyone seems to like ... and I've looked as I'd love to have something to stop the unravelling.