DSCN2910 I soaked the tank in vinegar for 24 hrs., rinsed it out well. I put in 4 lb.. of sodium carbonate and water to the top. I hooked it up to my 10 amp battery.
The positive lead to a stinger down the filler pipe. (not touching any metal) The ground from the tank to a headlight, to the charger. It loosened all the rust. I rinsed but there's a muck in there that will have to be taken care of.