komobu wrote:

Purchased a rental home with carpet from the 60's. It has nice hardwood
floors underneath. There are two 12 inch spots where the wood is stained
black. Do I need to cut these boards out or is there a way to bleach
them out or stain them back to their original color?

I also have pet damaged hardwood that I'd like to refinish. I saw a post
on a website that recommended hydrogen peroxide at normal drugstore
strength (3%). I was doubtful, but it worked well on the first black stain
I tried it on.

I did it like this: wet a rag or a few paper towels generously with
hydrogen peroxide. Lay the rag on the stain. Put a piece of plastic on top
of the rags. I set a pair of old work boots on top of the plastic to keep
the rag in firm contact with the stain.

Leave the rag on the floor for 24 hours. Then remove and let dry. The
stain should turn very light as it dries.

--
Tony Sivori