Tea, food coloring or fabric dyes can all be used to dye bone. Bone is a porous material that takes dye well, however care should be taken after the dyeing process to rinse the beads well. Since these dyeing mediums can be water soluble, the bone may not be permanently dyed. If so, there is a danger of fading from the sun or leaching out when exposed to perspiration. To protect the finish, you can coat the bead with a protective sealer such as Mona Lisa™ Metal Leaf top coat sealant.