My cozies are used for either a bowl of ice-cream or a warm bowl of oatmeal. I don't use the cozies in the MW as I don't want to take any chances. The concept of using them in the MW works for others but not for me.
I usually wait for items until I can use a JAnn's coupon to save costs. Perfect timing as W&Zap is on sale now for approx 2.90 per yard if you can use a bolt. Even the smaller packages are on sale. There may be other discounts for the weekend. Good luck with your projects.