Dan,
I guess I'll be the odd one out right now. I'd leave it as it. They may not be worth tons of money, but it has it's history right now and once you paint it that's gone.
It's not bad enough to really need it like my New Home (the mouse apartment) so I'd just clean it up and use it. I got several like that. One even has needle rash down to the bare metal and it's gonna stay that way.
Joe