I came across some spools w/o thread that needed to be clean. I put them in a zippered laundry bag and threw them in with some rags that needed to be laundered. Then into the dryer. If they're still a little damp when they come out, let them sit in a sunny window or area for a couple days. I also use the zippered laundry bag for strips and pieces of material for quilting. Old pillow cases work too.