Removing black stain iron or mold?

[Jack in omaha]

I am looking for best way to remove the black stain on this oak and is it iron or mold?

see photos

[Howard Acheson]

The bleach to use to remove mineral stains in or on wood is oxalic acid. Chlorine bleach and two part "wood bleach" are for other types of stains and have little effect on mineral stains. If the stains have deeply penetrated into the wood, multiple treatments may be required and maybe you will not get the stain completely removed.

BTW, mineral stains are black stains caused by metal reacting with the tannin in woods like oak.

[jteneyck]

The link took me to Goodwill Industries, not pictures of stained wood. But Howard is right, oxalic acid will remove iron stains, and you should be able to buy it at your local ACE hardware. If not, buy some Bar Keeper's Friend as it has OA in it.

Common bleach removes mold.

John

[Jack in omaha]

Sorry,
Sort through the 6 photos of the bank it is on side of box.
Bar Keepers friend has oxcallic acid would you use this?

http://www.uline.com/Product/Detail/S-20...mp;gclsrc=aw.ds

[JR1]

Sure that's the stuff. It is oxalic acid and an abrasive. Put a loose paste on and let it sit for awhile then wash it off. Don't rub it in.

[jteneyck]

Got it. I don't know what caused that. Looks like it could just be dirt ground into the finish. You may be looking at a sanding/refinishing job and, if that's the case, I'd consider just leaving it as it is, especially if the value would be compromised by doing it.

John

I see now it's not worth much. That being the case, I guess I'd start with OA, then bleach if that doesn't do anything, and then strip and sand the whole thing if it's still there. Not a hard job even if you have to go that far.

John

[Howard Acheson]

Bar Keepers may not have a high a percentage of oxalic acid as straight oxalic acid. You may have to use more or use multiple applications.

[Jack in omaha]

I did try bar keepers friend but since it is on the side it may be ink Here is another group of photos
<a href="[URL=http://s164.photobucket.com/user/johnnytanner/media/IMG_5620_zpswibugywe.jpg.html" ></a>]stain 1[/url]

<a href="[URL=http://s164.photobucket.com/user/johnnytanner/media/IMG_5617_zpshbzvmqzd.jpg.html" ></a>]stain 2[/url]

[Cooler]

I would try soapy water first. You really don't know what it is. I can't believe it is rust stains. Someone would have had to leave raw iron or steel in the box and it had rest against the side of the box. It sounds unlikely.

I have some rust stains on my floor from where the carpet padding was stapled down and the staples rusted. They are dark, but I suspect they are not very deep and may sand out with a single pass.

Until you buy this I don't think you can tell what the dark stain is. It could be a dark book was resting against the side and left some dye.

I think you have to buy it first. Sanding and refinishing the interior may all that might be required. Or if the box is historically valuable, then line it with fabric covered mat board that can be removed at a later date.

[Herb G]

That is mold on the bottom of that box. Weak bleach solution should take it right off. Just mix a cup in a gallon of water &amp; use a dish sponge to wash it off.
Rinse with clear water &amp; dry well.