I have made a number of the potato bags, always including a note that you should watch carefully the first time using it as some microwave have a very high wattage and could cause the potato bag to start smoldering. Only one person has had a problem. She used it on regular potatoes and used it often. one day she tried the little red potatoes and set it for the regular cooking time. It was much too long for the little potatoes and began to smolder.