Gas tank varnish

[BRENT in 10-uh-C]

Originally Posted by midgetracer

Has anyone had good luck cleaning old gas varnish from a model A tank. I have a 29 gas tank to clean that sat 30 tears with about 5 gallons of skanky gas in it. The bottom and sides are covered with a dark sticky varnish that keeps stopping the gas flow. I would like to clean it once and remove all traces of this old gas.

Order Sodium Hydroxide (Caustic) from a vendor such as Soapgoods and mix it up with water. This is what the radiator shops used some two decades ago and before to dissolve organic matter inside of radiators & tanks. Hot (--or warm) Caustic makes a great product for removing grease on Model-A parts.