The Warm co. has discontinued it.
To many people were having problems with fires in the Microwave.
The batting was probably not the issue, but when the bags were being assembled, the thread MUST be cotton. Not cotton/polyester and the fabric must be 100% cotton with no starch or even fabric softener.
I have discontinued making them for sale. Don't need the liability. I still make the bowls that are like a pot holder...but tell customers that I don't recommend using in the microwave.