Another effective way to purify a space is by burning a small amount of epsom salts and alcohol (denatured rubbing alcohol) in a fireproof vessel.

This beautiful flame clears the energy of a room without producing any smoke or ash.

Indoors: I use two silver wine goblets placed on a fireproof tray. Fill them 1/2 way with drug store epsom salts. To the salts add enough denatured rubbing alcohol to just cover the salts. Light with care keeping your face averted. The flame should burn for a good while.

Out of doors: use a shallow cauldron or metal container to burn a larger quantity of salts and alcohol. The upside down lid of a cast iron dutch oven works well as it is shallow and wide. Pour epsom salts and rubbing alcohol into your container. Some alcohol must float on top of the salts in order to burn. This will produce a wonderful flame to create a centrepiece for your circle. (an alternative to a small fire-pit.)

Warning: I would not recommend doing this with small or lively children present. Never leave the flame unattended and keep some sand on hand to extinguish flames if the goblets are knocked over.