I have some little plastic disks (for lack of a better word) that the bobbins can snap into, and then they fit on top of the spool that they come from. The size isn't right for all spools, but it works for most. It would only work if you store your spools on some kind of pegs to keep them from rolling around. This method works great for me. My thread is stored on those June Taylor peg contraptions. Mine are hanging on the wall.