Tough bleeding stain on cedar.

[acsipresident]

Recently I cleaned a cedar deck that is approximately 10 years old. The last time it was cleaned and stained was perhaps 4-5 years ago. Along the side of the deck are 2x14's that have dark bleeding lines running down from the surface planks that are screwed into them. I have already stripped all of the surfaces and now need to do the final cleaning-touchups before staining. These bleed marks are my biggest challenge. I've tried using Sunbrites stripper, Sunbrites EFC38 cleaner, some straight Oxalic Acid, some bleach and water mix... all leaving me scratching my head. Are there any ideas out there that I can try. My next step is to sand but it seems to me that there must be some chemical/cleaning solution to address this. Are tannin stains this difficult?

Thanks for reading and I look forward to learning some new ideas.