Fuel tank restoration

My procedure for cleaning a rusty tank.

With tank empty, outlet plugged, and dry inside, I pour in 1 or more gallons (depends on size of tank, 1g should be more than fine in your case) of Evaporust. Then I add a couple of handfuls of crushed landscaping granite and cap the tank so nothing can spill out.

Let Evaporust sit on rust affected area for 10 minutes and then agitate the granite. Let sit for 30 minutes then repeat. Continue repeating every 30 minutes until rust is gone. Rotate and agitate accordingly if you have other areas (sides, top) of rust you need to remove. Pour out Evaporust and remove all granite. Flush with clean water and get out as much water as you can. Then heat dry the tank in the sun or use a hairdryer or heat gun. Reinstall, fill with fuel, and enjoy your clean and rust free tank.