Bleaching dark spots on oak floor?

[GaryS]

I have a few areas where the polyurethane has worn off and the wood has turned dark. Is there a product that will bleach it back to the natural color, or must I sand all the way through it?

[pushkins]

There is no bleaching that will remove "dark sections" from oak floors. In fact bleach is not highly recommended for wood floors at all.
Sanding is the best thing you could do, BUT be very carefully howmuch you sand, if it's tongue and groove with is most likely you do not want to sand too far into the tongue or groove, this leads to a huge headache.