Wood – How to remove black rings on a wood kitchen top formed by a tin can

hardwoodkitchen-countersrepairwood

At our house we have a wood kitchen-top. We had placed on it a tin can (a typical cookies can), and probably because of some water sitting there, a black ring has been formed where the tin touched the wood. However, the tin does not show any signs of rust.

The kitchen-top appears to be made of hardwood pieces glued together, and only on the top and sides there is some kind of finishing, which has worn off at some places.

The main question is how to remove the ring. Some questions to which the answers would help are also: what is the stain exactly? how can we tell what finishing it has? can I sand it and patch it locally?

The whitening near the ring has been created by using household cleaning material because initially we thought it was rust sitting on top of the wood. We also thought it was a water stain and tried the iron-and-cloth solution, but that didn't work either.

I would like to avoid sanding the whole bench for the hassle that involves as well as the fact that I don't think I'm qualified for that.

Some images:

full ring:

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partial close up:

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Best Answer

Oxalic acid, either in crystal form or as part of a pressure treated deck cleaner/brightner will chemically dissolve the stain. If you use the crystals, use all normal precautions for acids (eye, hand, clothing). You can sparingly apply with a small nylon artists brush. Try 5 min increments (5 on, wipe off, 10 on, wipe off) until the stain starts to disappear.

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Once stain disappears, neutralize wood with borax diluted in water or bicarbonate of soda in water.

Replace color with dyes or pigment stains. I like Transtint for its ability to be blended and mixed with either water or alcohol. If you don't like the color direction, you can use bleach and start over.

Once happy with the color, seal it in with a dewaxed shellac. Then top coat with your favorite polyurethane. You may be able to blend the areas by shooting spray poly through a circular mask (5" hole in a 12x12 piece of cardboard, held 5-10 inches away from the floor) which will give you a graduated spray. Practice first.