Unfortunately, there is no easy way to get the sediment out of your fuel tank without removing the tank. First pull the tank and put something inside it to help loosen the rust, etc. Some people use a piece of chain, or bolts to loosen it. Then clean the tank out with a mild acid to etch the tank so you can pour a tank liner in it to seal up the rust and pits. If you are not comfortable sealing the tank you can take it to a local radiator shop to pour the seal.
JR