I have heard this works, but try at your own peril! preheat oven to warm, not 350. Turn off and place cutting mat on flat cookie sheet in the oven to relax. If you try this, let me know how it works for you. Just make sure that your cookie sheet is big enough. You might try doing the same thing in the trunk of your car on a sunny day, I know they get wrecked that way, maybe that can fix them, too.