Reaction of Butternut to Vinegar/Steel Solution
1) Place steel (nail, steelwool, etc) in container with White Vinegar.
2) Allow to soak at least 2 hours.
3) Apply solution to butternut.
4) After dry, burnish with something hard (antler, bone, etc)
Repeat steps 3 - 4 as many times as needed until desired darkness achieved.