I e-mailed my friend at Paintsource.net and here's what he had to say...Just another opinion:
"That is an interesting circumstance, and a solid answer. Oxallic acid is sold as “Wood Brightener” where deck or log home stains are sold. Most paint stores carry an oxalic acid brightener. I agree with the posts, that is a lot of tedious work, and gain is questionable to try and remove. The look could be “simulated” or enhanced as well,. I know craftsmen who will put thinned black paint or stain to get that effect, even on some old restorations. If it is a stain or pigment, and not tannin, then the acids will likely be ineffective.
I think the challenge is how different every project is. There are so many articles you could write with your experience. My main expertise is with the finishes themselves. My main thing to get across is that Waterlox is such a superior choice for character wood like that. You have to sand both oil and water-based polyurethanes for recoat, they look like plastic, and they show scratches tremendously (dogs and kids). Waterlox is the easiest to maintain and rejuvenate when needed, looks good longer, and requires no sanding for future recoat.
I will be happy to help any of your clients evaluate finish options. Please link to any information on our site:
My writing is not so polished, but here is our blog:
Please tell Steve “hey” from us.
All the best.