Originally Posted by
AZ Jane
Can be. They are made for warming up things, not for cooking. The problem seems to be when people put them into the microwave for 5 -10 minutes to cook, not 2 minutes to warm something up, like soup. I use them to make instant oatmeal and/or soup all the time at 2 minutes.
Anything will catch fire it you heat it long enough.
A sewing friend also found that her fabric scorched until she prewashed the fabric to get any chemicals out.