You've got tractors, right? Pull the tank, attach it to a tractor wheel with ratchet straps, and add a few gallons of water and a small bottle of dishwashing liquid. Toss in a few shovels full of gravel. Jack up the wheel, and put a jack stand or a stack of timbers under the axle housing. Crank up the tractor at idle, put it in gear, and walk away. Come back a few hours later to the cleanest fuel tank you've ever seen. The fun part is getting the gravel back out of it.
Jerry
