I have tried several ways to straighten out a mat. Nothing works. Put it in the hot sun with bricks on the corners, nothing. Tub of hot water and kept replacing the water to keep it hot, nothing. Iron the back. Steam the back. Used a hair dryer on it. I figured that if the sun can warp it in a car, then heat could help straighten it, no luck so far. Just bought a new one, but kept the old one, just in case.