Well as I feared the fella cleaning the tank wasn’t physically capable of lifting and turning it. Went to pick it up and we had good chat to what I needed to do.
He installed plug in the very corner to help drain, which didn’t make sense until he told me why. He is not quite 80, has and continues to rebuild radiators (old fashion way with brass and copper) along with fixing old gas tanks. His dad opened up business in 1919!! So the amount of experience this guy had was so cool to listen to and he didn’t disappoint.
The process he told me to do included:
1) fill tank with 3 gallons regular vinegar, fill rest up with water. Let it sit 4-5 days then rinse out.
2) plug shop vac up to where it’s blowing air in tank, leave it for 2-3 hours.
3) buy 4 gallons Red Kote, poor in sealed tank, manipulate tank in various directions to ensure entire interior of tank is coated. Take and blow brief amount of air inside inlet ports.
Drain using the new plug he installed.
Set open with fan blowing on it to help remove fumes, when no fumes present any longer than it’s coated.