You can go to a radiator/gas tank shop they clean and seal them but it cost.
Yours sounds like it could be flushed out by you with gas then put a see through in line filter on between tank and the fuel pump, most run steel line up close to fuel pump than rubber gas line the last foot or so before pump. watch filter to see if it gets dirty you can change filters for less than $5
Sounds like you have a baffel loose in tank?
