Water(?) stains on table

[richard b miller]

my wife is refinishing a dropleaf table and there are dark stains in the wood. its a solid top - black walnut maybe??
she's sanded the finish off and the stains still remain. any thoughts on how to remove the stains?
she has sanded them and they are in the grain, as in can't sand off without going deep.

thanks
richIMG_1522.jpgIMG_1523.jpg

[John TenEyck]

Try oxalic acid (available at your local ACE hardware store) in water on a small area, preferably on the back of one of the leaves if there are similar stains there, too. If it works, you likely will have to treat not just the stains but the whole top, after sanding or stripping the finish off, in order to remove the stains while keeping the overall color uniform. The color may change, but at least it will all be the same everywhere. Also, if the stains are lighter but still there you can repeat the process until they are gone, hopefully.

John

[Lee Schierer]

On a veneered top, I was able to remove a water stain by cleaning the area by wetting it with just plain distilled water. I had to do it several times before the wood evened out in color.

[Tom M King]

Sometimes a scraper will work, when sanding won't. In those cases, I thought that maybe the sanding might loosen whatever it is, and then grinds it back in below.

[richard b miller]

my wife purchased "bar keepers friend", made a paste and put it on the stains. she left it for 15 mins., then wiped off. THE STAINS WERE GONE!! its amazing!!
the BKF contains the oxalic acid.
John - thank you very much for that tip!!