so guys, I just picked up a 1992 zxr 250 and it has a piece of what looks like grey / silver compound sliding around in the tank. it looks like who ever tried to line the tank didn't get a lot of the remaining "stuff' out and a fair bit settled in the lower part of the tank and has now come loose. What can I do to get this out by dissolving it. it is larger than the tank opening. I'll have to then put some kill rust / phosphoric acid in the tank later too I guess.