Is it possible to exorcise ghosts if you e not a priest?
Yes, it is possible. In the Wiccan or "white witch" traditions, "cleansing rituals" may be employed to rid a place of an unwanted spiritual presence. This is not, I emphasize, "black magic" or "Satanic." For the details, simply Google "cleansing ritual" or refer to Karin Coddon’s ghost novel The Shadow Man, which details the enactment of a cleansing ritual toward the end of Part I. In brief, a cleansing ritual usually involves relatively easy to obtain materials such as candles, holy water, and sage sticks or "smudges." The person performing the ritual can either be the resident or a practitioner or white witchcraft. Incantations are used, which may sound arcane and strange, but actually have their origins in both the Judeo-Christian and older, pagan traditions. The sage stick is burned, like incense, throughout the residence haunted, especially in places such as doorways, staircases, or any other places where the spiritual presence seems especially strong. The same goes for the sprinkling of the holy water. It is a gentle and by many accounts highly effective way of ridding oneself of an unwelcome psychic being. Good luck with your ghost!
