The best way to clean it out would be to remove it and pour in some Chem-dip, normaly found in parts stores for dipping parts into. (Avoid contact with aluminum and your skin it contains methylene chloride and cresylic acid) Remove the tank, get out as much of the gunk as possble then pour the whole can in and let it sit for a day or two, swishing it around every so often, then remove the drain plug on the passenger side and flush the rest out with barsol. Then buy new or used sending unit and fuel pumps (you can't clean these and expect them to last). The whole nasty awfull prossess will take about 2-4 days to clean it to 98%.. P.S. Do it outside, Chem-dip is evil smelling stuff when it's working.
However my advise to you is: You'll futher ahead by replacing the tank and getting new or used fuel pumps and sending unit. And buy good gas, no more cheap junk from the mini-mart and run a injector cleaner evey other tank full. Also don't put any of those "make your car run better" additives in your tank either.
Last edited by Starmavin; 10-15-2006 at 10:40 PM.