Black Leather Dye from Iron and Vinegar (Iron Acetate)

Iron dissolved in vinegar gives a brown solution of iron acetates. Brushed on vegetable-tanned leather (or oak), it reacts with the tannin and turns black, the same reaction that ebonises wood. Put iron in vinegar, leave the lid loose while it works, then strain and bottle it. The picture: our diagram of nails in vinegar and the black stroke on leather.