Years ago I bought a perfect wraparound oil tank for a Panhead that the only flaw is that is was rusted pretty good inside.I had seen concrete etched with it when I was young and saw how it cleaned rusty rebar like new.I tried it,took 2 applications,came out like new inside.Then Sodium Bicarbonite and water rinse to neutralize it and immediately blow out with air and fill with WD-40 or the like to keep rust from forming,as it will almost right away.
