Need some help with my gas tank

[E36 guy]

I am in the process of trying to get an old 1984 Subaru GL running, and it has been sitting for YEARS! i think the last time it was driven was around 2004, and it had a full tank of gas....... which is now brown and disgusting. The fuel pump was bad so i bought a new one, and it still didn't suck any fuel through the lines. Finally i pulled the tank and drained all the fuel, and right as it was about empty a nasty black tar-like gooey substance was oozing out. I poured some in a cup to see what would dissolve it, I tried brake parts cleaner, engine degreaser, new gasoline, and even seafoam. Everything just sat on top and wouldn't mix or cut it down or anything.
Does anybody have any suggestions on what can dissolve this stuff down to make it so it can drain out? I have read somewhere that kerosine will do it, has anybody had this happen and had any success with cleaning it out?
I think the only good news is the fuel lines were dry, so I don't think it gummed up the carburetor.
Thanks for the help!

[isa2o3]

Try putting a lot of acetone in there and swishing it around (if you can) Best thing to do is replace it, but if you can't find one the lazy option = 32 Gallon Fuel Cell Reduced!

haha