Started my big project on my Sport. Pulled the fuel cell toady, and need to do some welding on it. Cracked bolt tabs and a previous owner had drilled a hole, tapped the 1/8" Al and "installed" a 3/4" street 90 for a vent off the bow end of the cell. Need to weld in a thread-O-let. Anyone know the best procedure for cleaning out the fuel cell prior to welding on it? I have flushed it with water a few times, rinsed it with dish washing detergent, and rinsed again. Might flood with Argon.