Cleaning rust from inside of tank...chemists step inside;)

[Royal Ryser]

JUST FOR INFO. On my 56 Bird, I had the gas tank cleaned at a radiator shop and then used POR 15 "Metal Ready", followed by POR15 "US Standard Fuel Tank Sealer." After about 3 years I bought a new tank due to a leak at the tank outlet. When I took the old tank off and looked inside, I found the Sealer was bubbled up on the bottom of the tank. I was not aware of any of the Sealer breaking loose and getting into the fuel line, etc.
Lesson for me, buy the new tank first and avoid all of the other problems.