clean rust out of a gas tank

[wyonorm]

I use water and pea gravel and then roll it.

[41ford1]

I used the electrolysis method. The electrolyte I used was water and Arm & Hammer Washing soda. 1/2 cup of soda to the gallon. Filled the tank with this mix. The electode was a 1/4" diam steel rod. The rod was suspended so it didnt touch the tank. Power was a 6amp battery charger. Negative lead to the rod and positive to the tank, power it up for about an hour. Rinsed with water then rinsed with alcohol and let it dry.