I now have several clear plastic thread spool boxes (stacked) purchased at the fabric shop. Years ago, before I had 1/4 of what I have now, I took a 15" square piece of plywood; placed a smooth floor thin underlayment piece on top of that and pounded headless nails into the boards, spacing them accordingly for the large and small spools. I didn't like that they caught dust and also took up a lot of space but it worked. I have purchased plastic cases for my embroidery thread (now need another one) -- chuckle