The pcs in one if my games will have the opportunity to teach a tribal medicine man how to make a medicine for his village. This will help them gain further favor before asking the chieftain for help. This is in addition to the good will gained by curing some of the villagers.
I'm debating which skill to have them roll to teach the medicine man. Knowledge education seems to cover the knowledge the character has. I've known plenty of smart people who can't teach. I've also considered leadership as leaders need to teach frequently. What do you think?