Removing stains in hardwood flooring
 

Hello. I am trying to refinish a section of my hardwood floor. There is a particular problem area where the wood is stained/dirty/discolored after the sand. The bare wood has become dirtier due to being exposed to traffic while waiting for me to figure out a solution before applying the finish. Does anyone have any suggestions for a good cleaner that can be used safely on bare wood?

1. mineral spirits

2. bleach

The mineral spirits will evaporate from the wood completely without leaving a residue. The bleach will have to be cleaned off with water. Both bleach and water will raise the grain of the wood.

If the discolouration of the wood is blue or black and was caused by watering potted plants that were sitting on the wood, then you're not going to be able to remove that discolouration. It's caused by the reaction of the tannin in the wood with the iron ions in water which cause a compound called "iron tannate" to form, which is also called "iron gall ink". If you suspect this is the cause of that discolouration, maybe phone some hardwood flooring contractors to see if they know any way to remove iron tannate stains from wood.

I think you can use oxalic acid to remove water stains; however, I believe it is also a bit toxic (although following link is a bit more optimistic):
http://www.alsnetbiz.com/homeimprove...alic_acid.html
good luck,
b

Bob:

Not saying it won't work because I guess anything is worth a try at this point, but oxalic acid is "wood bleach". It's used to remove the grey discolouration that appears on bare wood when it's exposed to the elements.

Wow, thanks guys. Looks like I have a couple options to try. I think I will try the bleach & or mineral spirits, because they are easily accessible. Were you suggesting I use them both & in the order you listed or one or the other? If that doesn't work, maybe I will try the oxalic acid. They are blackish stains & I know the wood was exposed to some water(but only briefly). The stains do seem superficial, more so than a plant pot stain anyway, so hopefully I will have some luck. Thanks again

No, there's no order, and I wouldn't use them together.

What I would do, however, is use an eye dropper to put a drop of bleach on the darkest of your spots and let it sit on there for an hour or three.

Then clean that drop of bleach off and see if that spot still looks the darkest. That will tell you if the bleach is doing any good at all.