Exorcise is the formal, technical term for driving out evil spirits, deriving from exorcism, an official ritual of the Catholic church.
exorcise:
1.to seek to expel (an evil spirit) by adjuration or religious or solemn ceremonies.
2.to free (a person, place, etc.) of evil spirits or malignant influences.
-- http://dictionary.reference.com/browse/exorcise
As an alternative, banish is a good general term meaning to drive out.
banish
- to expel from or relegate to a country or place by authoritative decree; condemn to exile:
- to compel to depart; send, drive, or put away:
--http://dictionary.reference.com/browse/banish?s=t