Spirit Exorcism is a powerful attack that allows a user of the Light Side to purge an area or body of foreign Dark Side spirits, banishing them to the nether of the Dark Side, never to return. This ability requires the utmost dedication to the Light Side as well as a keen understanding of the very nature of the Force. It is only effective against spirits, not still-living Darksiders.
Spirit Exorcism can be called in two ways. The more common method is for a group of Jedi to work together to purge the spirit, but powerful individuals are also able to perform the ability alone. In each case, the exorcism requires a great deal of power and usually leaves the user, or users, weakened afterwards.
A more advanced form of the exorcism, known as Force Light, is able to purge not just spirits but entire Dark Side auras or nexuses. Needless to say, it requires an even greater amount of power and mastery in the Force.