Fay,
Thank you. I am going to buy a package of the Warm and Natural Cotton batting and try it. I also use two layers and they are bulky when top stitching the edge. The package indicates it does have a poly type scrim but very small percentage of it. I also checked other sites and it was recommended by others who use it in the microwave. The Warm Company does not recommend it on their website, but they cannot I'm sure because of potential liability issues.
thanks again
evy