Varnished Fuel Tank

What is the best way to clean a gas tank with varnished fuel in it? I have a 14 gallon tank that had about one gallon of gas in it from eight years ago. I drained it and put new gas in but it just turned that bad too. I am looking for a way that is cheap to clean (possibly if there is some kind of solvent that will clean it.)

Thanks for helping me on this!

Should be steam cleaned and dried. Cheap? I haven’t a clue to cost.

Save money in labor, remove the tank and do the cleaning job yourself with a car pressure washer.
Make certain the fuel/water goes into a sealed container and NOT into the ground.

Alright, thanks for helping me on this!


Remove the tank and pour a pint into the tank, slosh it around and drain into an oil drainer - recan it in STEEL cans, repeat twice then flush with hot soapy water.

I use POR15 products on any gas tank before I refit :

Well worth the few dollars to prevent further corrosion problems, a good coat of Hammerite or Rustoleum finishes the job. You can install the tank and forget about it after that.