/diy/ - Do It Yourself

>>2448721
Remove the finish around the stained area, use oxalic acid to bleach the wood back, then refnish. It would be better to refinish the whole top, as blending finish can be tricky.
Do not sand the whole top, like that other monkeyman poster said. That's the cheap, stupid thing to do. You need to bleach the stain out, and at most remove the existing finish with paint stripper, and refinish the whole thing - and use a good poly to seal it so your non-coaster using ass won't fuck it up again.
There's tons of videos online showing how to use oxalic acid to remove water stains. Watch them. You can fuck it up even more making too strong a concentration. Luckily it's pretty light wood, so it'll be easier. Thomas Johnson on YT uses it all the time for this exact purpose, or watch this:
https://www.youtube.com/watch?v=BeR0MTPvHbs