Due to some stupidity and a large spill, I've got some nasty dark splotches on my wood.

  • http://i.imgur.com/4yQdwjU.jpg http://i.imgur.com/v8oxZKU.jpg http://i.imgur.com/H4YCfU1.jpg

I’ve sanded and cleaned I’ve cleaned the area with white vinegar (which might have been a mistake) and barkeepers friend.

Here’s what it looks like right now: • http://i.imgur.com/beuPk71.jpg

This seems to be more than surface damage and unfortunately it appears the stain has worked its way into the wood itself. Based on what I’ve read there doesn't seem to be a way to fix this without replacing the affected areas of the floor. I want to save this repair for further down the line (maybe re-do the floors at a later time)

In the meantime, barring placing a mat or rug over the damaged area, how do I cosmetically cover up this damage? I know (or at least I think) I can't fix this completely, due to the likely extent of the damage, but I’d like to make this area look passible.

One of my initial thoughts was to try a wood stain. Is it advisable to just try to stain the affected area and how do you effectively color match stains? I’d have some more leeway if I had dark colored wood but since this damage has seeped into my light colored wood – would a stain even be able to cover up and obscure the damage?

Are there any other materials and things I can try out and use to cover up this damage? Any other advice/tips?

  • Depending on what the stain was, wood bleach might be able to get some of it...?
    – keshlam
    Dec 9, 2014 at 1:16
  • I have worked with Oxalic acid, a type of wood bleach, has worked wonders returning wood back to its original color. Be careful with the 2 part wood bleaches, they will remove the color and leave the wood white, I have used those too.
    – Jack
    Dec 9, 2014 at 3:01

1 Answer 1


When using Oxalic acid, which usually comes in a dry crystal form, mix it with hot water, as hot as you dare, reading the labels for mix ratios. I mix it a bit stronger than they say, but that is me, I do stuff like that. You are new to this I don't recommend you do that, stick to the directions. While the mix is hot, pour it on the floor the same way the stuff that stained the floor did. Let it set as long as it takes to get into the same places as the fluid did that did the damage. According to the end grain discoloration, it was wet for a long while.

Keep it wet, keep the mix hot if you can, the hotter it is, the easier it works, the faster it will soak into the wood end grain. Do not let it dry out over the time while you are working with it, keep it wet.

If you went really overboard with the acid, I don't think you would ruin the flooring. Yes it will swell a bit, but it will dry back out. Any small gaps created by the flooring swell, will far less noticeable than the gray streaks the stain has. The trick about keeping it wet is, when oxalic acid dries it forms at the least a white haze. Not dry=no haze. If it does haze add more acid, a simple fix. The important thing is the cleanup. Have a clean 5 gal. bucket of water, a scrub brush and plenty of towels. Use the brush with plenty of water, drying it up with the towels. Do this 3 or more times, 5 is not out of the question, cleaning MUST be thorough. I had done this on wood walls with a hose and brush with constant running water and still had haze here and there.

Let the floor dry out for a couple of weeks before trying to repair the finish.

  • You also mentioned keeping it wet and not letting the oxalic acid solution dry out to avoid the white streak marks. What's the best way to keep it wet while waiting for the oxalic acid to seep into the wood after applying the oxalic acid solution.? Is the trick just to dab a little bit more of the solution or water to keep it moist while waiting? Sorry if this seems like a really basic question – I just don’t want to overdo it and create more damage.
    – StackFlax
    Dec 9, 2014 at 7:33
  • Basic questions need answers too. Just as you say, I would keep it wet by carefully adding more as it soaks in or evaporates. The idea will be to keep enough in place to at least soak in as far as the fluid did, that stained the floor. If it soaked in more, that would not be a problem. I would suggest using a small paint brush to apply and keep it wet.
    – Jack
    Dec 10, 2014 at 6:05
  • Thanks for the help! I hope Oxalic acid can restore or at least hide these black and grey stain marks. I know you said to avoid two part bleaches - do you have a particular brand you would recommend for me?
    – StackFlax
    Dec 10, 2014 at 11:33

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