Block up one wheel of your tractor or other appropriate vehicle. Strap tank securly to wheel and add whatever (gravel, old rusty nuts, bolts, etc.). Start and let tractor idle in first gear for the afternoon. Results, clean tank and nuts and bolts look pretty good too. Just remember, if tractor falls off block, there is no stopping it.
I'd go ahead and block up both wheels if I were you. LOL!
