I am also interested in how to prep tank to cut. I just picked up a used tank that has residual fuell oil in it. Also what is best way to clean. I know that fuel oil will not explode. My guess is to build a very large fire in it once the top is off and then once the fire is going place the top on so that the fire will also clean top part of tank. Any help from any one in this area would be greatly appreciated. want to do a suprise pig roast for my fathers 70th B-Day in late June. So time is getting short.