no scratches or anything just leaks
Well then you're in the clear
Seriously though i would be sure it is sealed properly. I don't know how handy you are, but you might want to consider breaking the tank down and basically starting with just a couple pieces of glass. You probably don't know how old or what the heck has been through. I agree get a razor, peel the piece apart and buy completely new seals and use this silicone gel everyone is talking about.
Thats just what i would do.