Tab,
I have removed many tops with the hammer/chisel combo. With a sharp chisel and heavy hammer it is amazingly fast, and sort of fun too. Wear a good glove on the hand holding the chisel. When done properly, it gives a pretty burr free edge. When the top drops into the barrel, leave it there...the bottom won't rust out as quickly. Be sure to slice air vents around the bottom to aid in combustion.
Stuart.
