I had some interest in my floor dilemma posted above, and with Bills help, I can honestly confirm the chemical that helped restore my blackened oak floors, "wasn't" vinegar, but bleach. But not just any bleach, but the concentrated version. I 1st tried my wife's regular laundry Clorox, and it didn't make a dent. But some-one informed me of the "concentrated" version, and it did the trick. I just found the same stuff I used years ago, and applied it to my tiger stripe, cause the vinegar, which sat all night, didn't do much. We'll see how this concentrated bleach does.
Here is the product that ruined my floor. The main ingredient is shellac. As I said above, it only happened on my oak floor, and I tested it on other woods, and couldn't get the same reaction.
And this is the good stuff. Always had good luck with Varathane, and is what I should've used in the 1st place.
The concentrated Clorox is what lightened my black floors, back to normal. But I can't emphasize enuff, it must say "concentrated", (in the yellow stripe), cause the other stuff won't work. I'm sure you ole timers knew this, and were sitting back chuckling, waiting for me to figure it out.