I agree with using coffee for bone beads. If you're looking for a natural aged bone look (kinda like nicotine stained teeth) then coffee's your best bet. I just brew up some coffee and let the beads soak over night. I don't boil my coffee cause i enjoy a cup while they're soaking. Also different roasts produce different shades. Light roasts produce lighter stains and Darker roasts produce darker stains. You can also use dyes for bone beads too. I've used the royal blue pro dye to stain some bone beads for a choker and they came out great. Just make sure to seal them with a stain or super sheen after wards if using dyes. Coffee is the best natural dye. I've even heard of some people using other natural organic materials also such as berries, cactus, etc. Anything organic can make a great alternative to oil/water based dyes. What'd you think mankind used before Fiebings? Yup! All the things growing from the ground. If you're eco-friendly at heart anything organic can be used. Just be creative! I've experimented with lots of different biological orgnisms and i've been happy with the result. Just make sure to test it first on a scrap before you're actual experiement. Boiling does help. I've seen a couple fully tooled purses colored with nothing but cactus oils and juice. The colors were amazingly bright. Be creative.