Vinegar Black

This is a product called Vinegar Black. It’s a traditional leather dye, but it’s effective on wood, tea-stained paper and anything else that contains tannins. Some people call it vinegaroon. To make it, you’ll need a quart jar, some white vinegar and a piece of steel wool. When the vinegar and steel mix, a chemical called Iron Acetate is formed. It produces bubbles when it’s dissolving, so don’t cap the jar too tightly or it might break.

Once it’s made, there should be no steel wool left and no smell of vinegar in the jar. If either are present, add the opposite. The reaction should take 2 weeks. As far as I can tell it lasts forever. This is also a good way to reuse old nails, since they’ll dissolve into nothing and you can use the iron as a stain.

https://www.youtube.com/watch?v=8jah2Tk4OQY