Sage has been used amongst healers and traditional cultures.  When sage is burned it releases negative ions which has been shown to help improve mood.  It also clears 94% of airborn bacteria.  In more traditional terms sage is used during many ceremonies to clear negativity and remove spiritual impurities from people, spaces, and objects.  It is recommended when using sage that you open the window so the negative energy has somewhere to go.  Sage has been said to bring in spiritual awareness.  Sage is not something that is used to clear out spirits within a home but white sage smudge sticks have been used throughout history for lightenting the energy of the room.