I bought a cheapie atwood plastic tank from walmart several years back, it's been poofed out so many times from the sun shining on it and vent closed that it doesn't sit flat on the bottom anymore, it's like a weeble.I bought a outboard reciently, and it came with an old mercury kiekhaefer steel fuel tank. The tank is ok shape, i was wondering if somthing like that is any value? Thanks