Ancient bones (The Restless Ghost)

Ancient bones are obtained by speaking to Father Aereck in Lumbridge Church after completion of The Restless Ghost quest.

Father Aereck gives the player 5 of these bones as a reward and each bone gives 200 prayer experience when buried.
 * When used on the Wise Old Man he will say that he wouldn't know whether you should keep it or not since he can't identify items from members-only quests although the bones are obtained after completing the free-to-play quest The Restless Ghost.

Ancient bones are also a good way to get your Prayer level up.