You should read the instructions on the hook and loop that you purchase, but generally it is okay to put it through the dryer. As for the microwave, my understanding is that only 100% cotton should be put through the microwave. This means the fabric AND the thread used to sew it must be 100% cotton. Even then, you can start a fire if you put completely dry materials in the microwave; it's safest to put those items through with a cup of water. Hook and loop is made of nylon and I would avoid microwaving it, just to be safe. If you want to risk it, you could always test a scrap of the hook and loop on a plate (include a microwave-safe mug full of water) and see if it melts. Hook and loop that's stick-on may come off when heated. Adhesive tends to unstick when there's a lot of heat from a hair dryer, dryer, etc.