My mat started to warp for some reason in the middle at an angle. I did the frozen cookie sheet method. Dh had a piece of 4x4 plywood and we put the mat on it and a piece of fabric then the cookie sheets on top of it and had a couple large old dictionaries and placed it under our bed. That way everything would be flat. I didn't want the cookie sheets in direct contact. was afraid what would happen because of the heat and cold. Worked fine. That was last year.

I think it was Superior Threads that also recommends using ice/very cold like Citruscountryquilter mentioned.

Jan, love your idea! Just had a discussion last night with my quilting buddies on getting the warp out of a cutting mat. I will tell my friend what you all have suggested.
Thanks!

great idea jan i have always been told never leave in sun or hot car!

Jan,
The mat carrier idea is brilliant! I'm going to make one today! Adding the flannel is inspired!
Kathie

Thanks Jan for sharing. Fab I heard HEAT can wave a cutting board, especially in a car on a hot day.

Jan, you totally amaze me!

Wow, Jan......great idea to keep a mat flat for transportation or storage. I'm amazed at the simple, wonderful ideas and tips that are posted on this board. Thanks, quilters!

I have placed a mat in the sun and it flattened. However it took days, when I had given up and brought it in the house it flattened.

Hello All!
When I moved last summer thought the car was a safe place to transport my cutting mat. Wrong if it is not removed very soon. It warped badly. Just laid it in the drive way or front step in the hot sun two or three days, hottest part of day. Brought it in overnight and laid flat. If warm when you bring it in lay flat. Not a ripple after that. It is a Fiskars and I have had it for several years. Possibly different material than mats are made of now. As mentioned, try different things if you cannot use the mat at all.