Almost every old farm implement will have rust on it, and tractors are no exception. It's easy for tractor gas tanks to become rusty since they're not always used every day and are often refilled with gas cans that can contain significant amounts of water. An electrolytic bath can clear up most rust from the interior of a tractor gas tank.
Remove the gas tank from the tractor and place it in a tub. Fill the tank with a solution of one tablespoon of lye or washing soda for every gallon of water.
Use a steel rod that you won't use again as an anode. Clamps should support it, keeping it away from direct contact with the gas tank. Attach one wire to the tank and one to the anode. Let the wires dangle over the side of the tub.
Connect the black clamp of a battery charger to the copper wire attached to the tank. The red charger clamp should be connected to the copper wire attached to the anode.
Plug in the charger, being sure it goes into a GFCI, or ground fault circuit interrupter, outlet. The solution inside the gas tank will begin to bubble. Let the charger run for about eight hours. Unplug it and drain the tank. Wash it out to remove any residue that didn't attach itself to the anode.
