Cleaning a Gas Tank

[Vic in E-TN]

I am trying to finish a late 31 Coupe project that I started about 12 years ago and did a few things over the years like accumulating interior, changing the Rumble Seat to a trunk, getting a leather seat done, etc. I needed to get it running so I could move it to the work area. It runs OK with a 1 gal gas can on the radiator rails. I drained the gas tank and not much came out until I put some air into the external drain. I put it outside and put 10 gallons of water into the tank and it mostly came out without much trouble. The last liquid residue in the tank is very red and smells terrible. There did not appear to be much rust in the water drained from the tank as I was planning to follow some advice here and use Rust 911 as the last step. I have a gallon of 5% vinegar to use as the first step to clean up the unknown red residue.


I am looking for advice or warnings before I put gasoline into the tank after all the cleaning steps are completed. I am concerned about the acid in vinegar. Your thoughts please.


Vic