I have the boxes that are meant to be used for "match box toy cars". My spool of thread with matching bobbin (a small pony tail elastic is around the bobbin)) is placed in each compartment. Spools of thread that have not yet been used, I keep sorted by colors --red/pink/purple, blues/greens/, white/black/grey, yellows/browns--in plastic shoe boxes--marked on end of each box so I can easily get out a new spool of thread.