Vinegaroon (aka vinegar black) is mixture that alter the chemical composition of leather dying it permanently black and it will not rub off on you clothes etc. I purchased a few different tape measure holsters to hold my PKE, sound level meter, and build some belt gizmos. These all started off as natural/tan leather and with about $3 worth of steel wool and vinegar they are now a nice deep black. I followed the instructions at the site below vinegar+steel wool for about 1 week, a quick bath for the leather and them a few minutes later another bath in the baking soda and water.
https://www.adamsleatherworks.com/vineg ... gar-black/
You can see my results below. Unfortunately I didn't take a before pic but all 5 holsters were originally the color of the upper right hand holster. The upper right hand was the only one to resist the chemical effect and must of been treated/sealed before hand. Unfortunately I have no way of telling if leather has been sealed but is was definitely the stiffest of the 5.
Hope some one finds this useful! Thanks