On the wooden ones.... I have a bunch of them from my Great Aunt Sally. Most are silk buttonhole twist. I finally had to go to YouTube to find out how to do handmade buttonholes to use them. It truly is beautiful stuff if you're into that sort of thing! I'm sure you could use it for embroidery as well - with those iron-on transfers. There just isn't much on a each one. And THEN - sell the wooden spools!