I've got an '84 LS that had a rusted tank and missing liner .
If you've ever heard about using molasses and water to remove rust, I tried it and it does work, but it takes a few weeks .
The by-product of molasses and water after a 'fermentation' is acetic acid, the acid in vinegar .
You can use vinegar and it will remove the rust and old liner .
One of our members here, Crossrodes did this last winter, you may want to send him an email, as he doesn't log on here to frequently now and ask him about what he did .
Another method of removing rust, but not so sure if the liner would come off, is electrolysis .
After you get the rust and liner out, put phosphoric acid in the tank and swirl it around to treat the bare metal .
I used the POR-15 kit .
Doing it again, I would just get the sealant and not the kit, for a really rusted tank, the two bottles that are in the kit just won't get the job done .