We just had new hardwood flooring installed on the first floor and stairway. Unfortunately, our dog has slipped and fallen down the stairs and scratched the polyeurethane. None of the scratches seem to have gone deep enough to reach the stain but there are a couple of scratches in the poly. We plan to install a carpet runner on the stairs but I wanted to know if there is a way to "fill" the shallow scratches in the ploy before I cover the stairs with the runner. It's a dark cherry finish.

If the stain is not scratched, just the poly, you can add more poly with a very narrow brush. I'd mask the scratch with painters tape for two coats, then remove the tape lightly sand with 320 and then a blending coat of poly. Just be sure to use a poly like you have now, same stuff if you can get it.

Scratches and imperfections happen in hardward flooring and is considered charactistic for the most part. If the scratches are not bad, no harm in leaving it if your going to cover it up any way.

But, if it really bothers you, then what is suggested above will help.
- wear a mask when you use poly, and not just a light dusk mask either. Have ventilation.