You can also whiten them up a bit and give them a good cleaning by boiling them in a one part water / 2 parts hydrogen peroxide solution with a couple teaspoons of "409" cleaner poured in. Slowly boil them for 15 minutes, let the water cool, then boil them again in fresh water for 15 minutes. You can polish the tusks by sanding lightly with 400 grit wet / dry sandpaper, and them buffing them by hand with any kind of white metal polishing paste. I use this method on turkey wing bones to make calls. I have found that using bleach can sometimes make them brittle.