Got th e crud and rust boiled out of the gas tank and I've got a can of Por 15 Gas Tank Sealer. You can see from the pic that there are remains of the previous sealer in there. I think it may have been resealed before with a product I saw on the net- red-seal or something like that, that described how it was descernable by its red coloration. I figure I've also got some residual rusty spots inside that COULD BE neutralized with muratic acid (rust neutralizer- converterer), but that may not be good with the tank sealer. Are there any readers who have done this and have observations to share?

Yep... I have used muriatic acid and a couple handfulls of big rocks dumped into the tank followed by a lot of vigorous shaking with good results..

What to watch for is the acid eating the rust away and causing fuel to seep through the tank (the sealer usually cures this) as I had this happen to an old Farmall Tractor I restored...

If using the acid allow the tank to thoroughly dry before applying the sealer. I have even held the tank up to the exhaust of a car and used the exhaust to neutralize the acid fumes in the tank (this also works if you ever need to weld on a tank)

I used the POR 15 on Beth'e convertible project and used the muriatic, rocks and sealer with good results. Just make sure the sealer doesn't block the fuel outlet ...

Thanks very much!