Q: What is the best way to remove watermarks from my wooden floor? My cat keeps splashing water on them.
Can I just put a fresh coat down of polyurethane down?
A: What colour are these marks? Are they black? If so, that will have to be removed. You could start gentle and get more aggressive as needed. Start with steel wool and go to sand paper or a hand scraper if needed. Then apply several thin coats of finish to the spots. Note it will look different than the surrounding floor.
Follow-up: The marks on the floor are white.
A: It sounds then like moisture has gotten trapped in the coating. This is something more typical of shellac. You could try an iron on a towel over the spots to see if the heat will draw out the water. Be cautious.