I am so glad to have come across this posting. Thanks for the really good ideas for repurposing a mat that you aren't using for whatever reason. I'm going to try some of them.

I saw purse bottoms mentioned, but I'd use pieces anywhere I'd use chip board like in e-reader covers, journals, fabric boxes etc. Rescue a sagging chair or couch. Shelf liners.

This is totally tounge in cheek. A quilters checkers game for a guilds white elephant. Color every other square with sharpie and make two colors of chicken pin cusions. Must yell "pin me!" instead of king me.

I cut up my old ones to size to fit one die shape on my Go dies. It works fine and I can cut more layers of fabric using the thinner mat. Sometimes I just want one die shape so no need to have the whole die cut mat being used and worn. No mat covering the blade, the blade does not come out of the foam. I don't baby by Go machine or dies. I use the fire out of them.

Not re-purposing ... but FYI I have had luck with getting warp/buckles out of self healing mats (mine is an Omnigrid). I had stupidly IRONED something on it. Yeah I know ... not one of my brightest moments.

Anyway .... if you want to re-use the mat as a mat, or need to get the warp out to use it as something else, you might be able to fix it. I use the same fix that I use to give my mat a good cleaning (and "healing").

Saturate several towels with HOT water. Spread the towels on top of the mat (the mat should be on a flat surface). Place a piece of plastic over the wet towels, then place a lot of books over the top - make sure the books fit snugly to each other so as much as the mat is covered with weight as possible. You may need several layers of books. Leave the mat like this for at least 2 hours.

Have everything ready before hand - books, plastic sheeting. The sooner you place the weight onto the hot wet towels, the better.

If they are warped, they are useless. If you have a brand you don't like, offer it in a garage sale. All my quilting stuff with the exception of some thin fabrics, were snapped right up.

This is a great thread - got several ideas from y'all. Thanks!

Buy a wooden Lazy Susan from Walmart (usually 12" round). From the old cutting mat cut out a circle the same size of the lazy susan. Glue onto the lazy susan with a thin but strong glue especially around the outer edges. Now you have a rotating cutting mat to accurately cut those small quilt pieces.