Vinegarood will give a very deep, almost black brown. Just take a small jar, put in a handful of fine steel wool and fill with vinegar. Put a hole in the lid to let air escape. After a week or so, you should have stain. The stain reacts with the tannins in the leather. Within seconds of wiping it on, the leather will turn a grayish black. Wipe it down with a cloth soaked in a baking soda solution, to neutralize the acids. If you want, you can go over it with brown shoe polish, then a generous application of mink oil.
Kyle
