I stripped the old stain off of my 10+ year old redwood and then used an oxalic acid brightener.
But I have quite a few dark areas on it. I can sand them off but it is a lot of work.
Any ideas for removal before I stain?
Depends on what the dark areas are exactly. Please add a picture.
here is one
Hard to tell. Is it old stain that did not strip off completely?