There is a 100% cotton batting sold at most LQS for this purpose. Do not use Warm and Natural/White as it is NOT all cotton. The same should be true for bowl mittens. You must also use cotton thread. The potato bag also makes awesome corn on the cob. You roll each ear in a damp paper towel. My m/w is 1050 watts and I do 2 ears for 5 min. on high.