did you know that the nickel sized fits about 5 bobbins, I use them to store my half used bobbins, my needles of different sizes, also when I am working on a large project and know I will be using several bobbins worth of thread, I will load up about how many I need and store them in one of these tubes next to my machine.
the half dollar size is useful too, when ever I am doing some hand sewing (binding or applique) I will put a needle, some safety pins and my spool of thread for that project in it.
you can find them at coin stores and some hobby shops like Hobby Lobby carry them.
just thought I would share that