Many painters and homeowners use it to wash decks, rinsing it into their yard, before painting it. This is why it is called wood bleach and is sold at paint stores like Sherwin Williams.

If you do a search on oxalic acid, just remember, you will be using it as a very dilute, less than 1% solution. I put one to one and a half tubs of oxalic (about 18 ounces) in an entire kiddie pool of water (thats less than 0.25%). Of course, while handling the crystals themselves, you are handling it at full strength.

But if you are uncomfortable handling oxalic acid, or any other chemical product, then you should avoid it.