Those bowl holders are NOT for microwaves either. They are for the table, like a hot pad, has nothing to do with cooking. If there is any polyester in this made item, it will burn at a low temp. A fireman friend has a fit when he hears people talking about them and will tell crafters at shows they could be held responsible for a house fire if someone buys from them. Don't use potato bags in the oven either, please folks, just don't. Being a fireman for many years and then arson investigation, he knows his business.