How to clean pet residue/stains on old hardwoods under carpet
I pulled up some carpet in our two upstairs bedrooms and could use some advice. The house was built in '61 so the floors are old oak. I removed the old carpet, tack strips, and carpet pad, and while one room is in relativly good shape (needs a good cleaning) the other has what appears to be pet stains that soaked through to the hardwoods. I'm trying to figure out how do to the following so I don't have to refinish:
1. Remove crystalline residue near old transition, appears to be dried pet urine. Tried swifer hardwood floor cleaner to no avail.
2. "clean" black stains on hardwood that appear to be old liquid (possibly pet) stains that had soaked through carpet.
3. Reduce visible scratches/holes caused by lame carpet installers who put staples in the pad every few inches, some of which not only left holes but left scratches.
I know this is a lot, but really what I'm looking for is a good hardcore cleaner that will remove everything except the polyurethane and something else that might help "hide" scratch marks, etc. I'm not holding out hope for the black stains, but someone I know recommended bleaching them, which I've never heard of.