I have . Piece of cake. Don't just cut a big hole in it use a big hole saw instead, and cut several holes all bunched around each other...it will act like a slosh baffle. Just wash it out two or three times with super hot soapy water and weld it up. No big deal. If you are nervouse about welding on the tank you can back purge it with argon while you weld to prevent a kaboom ( I didn't..just washed out good) I have heard that running a car exhaust into it would be an option too...but can't varify that.