I have a T-Dub with a bit of surface corrosion in the tank, all I did was swish fuel around in the tank and then dumped it out a couple of times, then I took the petcock out and cleaned the screens for the main and reserve sections. I do, on a regular basis back out the drain screw on the bottom of my carb to drain any crap and corruption that may accumulate over time!
There are a couple of internal coatings that are available, but if my tank was that bad I would find a replacement tank. You may benifit from adding an in-line filter to your bike!
Good luck with the new machine!!