Like I said - don't hone. A bore mop is something that you should have in your box anyway. So is a container of Flitz or Bore Shine. They are only a couple of bucks at Wallyworld. A container of Flitz is only a few bucks too.
Yes, the old gal is worth cleaning up but I wouldn't put any money into "fixing" anything really broken. It isn't worth a lot of money. I'd say the $50 you paid is about right.