If I lined up every sheath I have made, people would accuse me of being like Henry Ford with the Model T - "You can have any color you want, as long as you want black".

For the first few sheaths I made, I used a "Fieblings brown" from Tandy. They came out looking more like mottled snake skins with mange. I don't know if I had a bad bottle of dye or if the hide I was using came from a Martian cow but the only way to "fix" them was several coats of black. Also, before I had the revelation that I should either drill my holes bigger OR use a thimble/push pad when hand sewing sheaths, I would end up poking holes in myself

and leaving blood spots/streaks that could only be covered by black.:grumpy:
Since then, I've stuck with black. I'm now working with vinegaroon.
I had a mountain man guy who wanted a "really rough looking Bowie knife sheath" to look "as authentic as possible" that it had been "cobbled together" with spare parts. I went looking for a way to "color" the leather like a mountain man making up a replacement sheath in the boonies might go about doing it. That lead me to vinegaroon. While no mountain man in history would have had a bottle of vinegar and a pile of iron shavings to make it out in the boonies, I thought it might be "old timey enough" that my guy would accept it. He did and the rest is history.
I really like working with it - no dye all over the place, no extra waiting for the dye to dry, only 1 application and the leather is black all the way through.