What to do with your old yoga mat

Use it as a nonstick mat for the trunk of your car or put it on the back seat to protect the upholstery from the muddy feet of your dog.
If you like extra cushioning under your yoga mat when doing yoga,  put it under your new one.  Or cut it up for knee pads when doing kneeling poses.  Or roll up the old mat and tie it together to make a bolster when you need support in floor poses.
Go to recycleyourmat.com to recycle the mat if necessary.
One more option.  My husband often asks if I have any old mats I want to get rid of.  He has some ideas on how to use old mats too!
What else could we do with our old mats?