I have used Rit on deer bone. I boil the bone to get it clean, change the water and boil it again with a little dish liquid to remove more of the oils. Keep temps just high enough to boil and let it cool slowly. High heat and rapid cooling = cracks. after its nice and clean let iy dry several days. If you can put it in the sun a few days, I think it gives you more of the tiny cracks that give it character. Put enough water in your container to cover the bone, add enough Rit to get a nice rich color and bring it to a boil. Turn off the heat and put the bone in. Check every few minutes until you get the color you are looking for. when still wet you can rub with a rag to lighten the colors in places for contrast if you'd like. Let it dry for a few more days and you're ready to go. Like anything I'm sure there are many ways to do it, that's just the way I do it. Hope this helps.