Where can I buy oxalic acid crystals?

I’ve purchased oxalic acid crystals from my local drug store. Sometimes it must be ordered, so you’ll need to ask. I also had to sign a book and describe my intentions for using the substance before they handed over the bottle. One thing you need to understand is that, while bleaching wood does remove stains, the results usually aren’t perfect. Also, bleaching tends to reduce the variation in grain colour, so the wood doesn’t look as vibrant.