Black Stains On Cedar?

[Joe Wood]

So, these are some 6x8 wr cedar timbers I'm going to keep rough sawn, with a light sanding. Do these black stains look like iron stains to you? You think oxiclean will get them or is oxalic acid whet I'll need?

[Doug Garson]

Check out this video, a bit long winded but might give some ideas.

https://www.youtube.com/watch?v=4Un0mjkadLo&t=1002s

[Joe Wood]

Thanks Doug but that video says nothing about getting rid of the black stains?

[Kev Williams]

if you have a pressure washer, try that....

[Maurice Mcmurry]

Looks there might have been something iron sitting on top of them. Or tannic acid from oak stickers. Also looks like it could be mold. Those are lovely chunks of wood!

I would start small with a tooth brush and mild bleach solution, working up to straight bleach, if nothing happens with mild.

Doug, I liked the tips in the video. I have to make faux barn wood sometimes and use a wire wheel in the angle grinder. It is good to know about the Restorer. The Next Level guy does improve black marks with the restorer, 31:40 minutes in.

[Jim Becker]

While there can be many causes, I agree with Maurice that the most likely for dark staining was the presence of iron (nails, screws, etc) in the tree. You can try and bleach it, but it may be pretty well ingrained (pardon the expression) within the wood, rather than just be on the surface.