Now for my method! First, find an old hair dryer, the type that had a hose
on it. Discard the plastic head cover. Now, fill the tank with water, and
empty. Do this three times. Now, insert the hair dryer hose into the filler
hole. Turn on the dryer. The hose is usually smaller then the filler hole,
so air can escape. let it completely dry the inside of the tank. Weld
immediately. If allowed to sit for a while, the adsorbed fuel molecules on
the inside surfaces may slowly evaporate. This can form a combustible
mixture.

Steve R.