[pat in Santa Cruz]

if its dried gasoline, a radiator shop chemical boil out will do it. But if its rust or old tank sealer, the baffles will prevent any large media from getting at all the rust or liner behind the baffles. The only way is to cut out the back of the tank and bead blast it. Then weld it back up. If you do not know how to weld a gas tank, don't try it. Send it to Brent.