Fuel Tank Removal

If you have ALL of the gas out rinsed out and gone completely, throw a match in and make sure it is all gone. you can get it airtight and hook some compressed air into it like 5lbs and heat the dented area with a torch. it'll pop right out to its original shape. And if youre still scared to try it put some dry ice into the tank to keep it from xploding.
Of course i would never recommend anyone try this, but that's how we used to fix our gas tanks when we were young and dumb