This gas tank sat up for over thirty years and developed about half an inch of total rust inside the tank! I poured Evapo-Rust in the tank to remove the .5 inch of rust scattered about. Worked like magic! I then washed the tank out with soap and water and aired dried really good, then poured Bel Ray two stroke oil coating the tank to prevent flash rusting.
After a day just out of curiosity I checked the tank, major flash rust all over! You could see the rust underneath the oil. Evapo-Rust saved the day again but this time I didnít soap clean, I simply left a coat of Evapo-Rust on until I get the tank painted and filled with gas. So far its lasted three week with about .25 inch total rust.