I use an old school method of cleaning a gas tank- - - - -put a couple of shovels of gravel inside it, strap it to a rear wheel on my tractor, and spend a couple of hours bush-hogging one of my pastures. It does a really good job of dislodging the crud in the tank, but it also finds some pinhole leaks that the crud was plugging up, occasionally. If buying a new tank won't make your checkbook need CPR, it's a much better choice!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!