I attempted to remove the red oxide primer from inside my tank. I tried solvents in a reasonable order (reasonable to me).
Turpentine, did nothing. Lacquer thinner, did nothing, Acetone, might have worked if I had 2 years. Ethyl Acetate, really did soften the primer, I could wipe it off anywhere I could reach inside the tank quite easily. Zylene (sp?) would have been next, but I just ran out of caring when there were no more chunks, just red staining in the solvent.
The real problem comes in that you cannot physically reach everywhere, making complete removal impossible. Even with 30 drywall screws, and 25 washers swirling around in there, there are many dings inside from forming the tank. Its honestly just too much work to worry about. I am not big on tank sealants, and just did not want big gobs of primer floating around.
Complete removal is going to be a time thing for me. I probably removed 65% of it, I will run a very good fuel filter and change it when needed. Eventually, all the primer will be gone and I will be too old to worry much about it by then.