I've seen them carved like a vintage Santa head.

I have used them on a wall hanging. I made a casing on the back of my wallhanging the right size for a 1/4 inch dowel to go through at the top and bottom edges. I left the dowel sticking out on the corners and pushed the spools onto the ends and glued in place. Looked real cute.
I also saw a picture of some used on a window valance. They puts multicoloured fabric strips hanging from the rod and pushed on an empty spool (like a bead) and tied a knot after the spool.

Sure glad you are not throwing them away. I have a few displayed nicely in a glass canister.

Please don't throw them away...if you don't want them at least give them away to someone that can use them.
I have a couple of ideas for making them into ornaments which when I have some time plan on making for gifts for quilting friends.