I am interested in doing this also. I found this post on a search. Did you end up doing anything?

Here's what I did on my maple floor that was under some 1950s carpet. Since we knew it wasn't polyurethane, my local shop told me to clean it really well and then apply Benjamin Moore's Antique Oil. That way the maple kept it's nice patina and didn't have the bleached, new look. She also told me if an area got worn after a few years, I could just repeat this process on the worn spot (I haven't had to do that yet and it's been 8 years).

The finish is really nice, not plastic at all. It is a little shinier than I wanted, but it was an inexpensive way to clean up the this hidden treasure.

I can email you a photo if you'd like.

Here are the instructions I followed:
½ bucket of warm water
1 cup mineral spirits (turpentine)
½ cup Murphy Oil Soap
½ cup denatured alcohol

Work small area at a time. Scrub lightly with #000 steel wool. Wipe of residue with clean cloth in alcohol only.

After 24 hours, apply 2 light coats of MooreÂs "Antique Oil" with a soft cloth