I have literally made hundreds of these - Learned the hard way - the more powerful ovens will catch them on fire - never use more than 1000 watts. Also the moisture in your potato can cause a hazard. Potatoes that have begun to wrinkle will cause problems. Always use 100% cotton fabric, batting and thread. It's better to heat 2-3 minutes, wait a minute or so and then give it another minute or 2. My customers love the taste of potatoes cooked this way. I also cook sweet potatoes, corn on the cob and warm hard bread. For the bread just sprinkle with a few drops of water and only cook for 15 seconds or so. Again wattage of oven makes a huge difference.