
I have solid poplar floors with wood plugs to hide the screws. Recently I noticed this yellow stain around many of the plugs. The floor is finished with polyurethane. What might be causing it and what should I do to fix it?

I have solid poplar floors with wood plugs to hide the screws. Recently I noticed this yellow stain around many of the plugs. The floor is finished with polyurethane. What might be causing it and what should I do to fix it?
I am assuming that this has 'always' been this way and you just recently noticed it, because it looks like glue or wood-filler got smeared on when putting in the plug and they just poly'd over it. It is possible that as the wood has aged that it has gotten darker making the contrast more obvious.
As Graphus pointed out in the comments sanding it down and re-polying it are really your only options. Whether you decide to rent a floor sander and do the whole thing, or try and spot sand with a hand sander is up to you, but I'm guessing with the color of the poplar in the photo, spot sanding will lighten it up A LOT and make it look like an inverted Dalmatian. So my recommendation is either do the whole floor, or live with it as is...