In the Dungeoneering place, I just found out that players can use any bones they find off of dead enemies and use them on the alters for extra-bonus Prayer exp. This isn't just an additional point on top of whatever the bones are originally worth, this turns a normal set of bones from 4 exp to 18 exp. This might not sound like a lot, but it greatly helps when trying to get those hard to earn Prayer exp points. The occasional big bones are much much greater, but I do not have the exact number. Hope this helps
