Hi, I just refinished my wood floors. A couple had surprises hiding under old paint.

In the 1st attached photo, there is a black stain, perhaps part of a past adhesive or something. Sanding down further into it slowly removes it but it seems to have penetrated the wood. I don't think I'll be able to remove that. Any suggestions of what to coat this floor with?

In the 2nd photo there is more of a black tar-like substance, presumably an old adhesive. This I found in two rooms, in one case below paint. It is scrapable and I have tried an adhesive remover on it. However, in either case, I can't get out 100% and the sanders just kind of spread it around a little bit. So, while the large streak in this photo is 80% gone and the boards with small streaks of black are now less so, there is still are faint black streaks throughout two rooms. I'm assuming if I coat it with poly, the blackness with be pronounced? Any suggestions for coatings / further removal?

Thanks!

 

An adhesive should scrape/sand off, water stains are more apt to go deep into the wood and need to be bleached out with a wood bleach [not household bleach]

A dark stain will make the black marks less noticeable but a light stain or just poly will make them stand out more.

 

Wood bleach would be my thought as well.