I have had a potato baker bag for 10 years and have used it quite abit. Time my potatoes for 6-1/2 minutes and have never had a problem. I have made the microwave bowl holders for 5-6 years now using warm and natural only for the batting inside and have never had any problems but have never warmed anything for longer than 2-3 minutes. They are used for warming and not cooking and one must remember that. I have never heard anyone that I have gifted them to or sold to complaining about any problem but I stress the warming and not cooking aspect.