Pellon makes a product called Wrap N Zap, which is 100% cotton, no scrim. I found it at JoAnn's and it can be ordered on line.
I just finished making around 24 fabric bowls for Christmas presents, and I made up a little instruction sheet to go with them. In it, I specifically state that the bowls are 100% cotton and can catch on fire if left in the microwave too long, and for safety sake, not to heat anything with the fabric bowl for more than 3 minutes at a time. So, zap the food for 3 minutes, stir and check temperature, then continue heating if necessary. This is the method I've been using with mine, and so far (3 months), no fires.
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