The cedar tree is known for its spiritual significance for thousands of years. Its wood was used for the doors of sacred temples and burned in cleansing ceremonies. The cedar smudge is mostly used for protection, also to cleanse a home when first moving in, inviting unwanted spirits to leave and protecting a person or place from unwanted influences. The smoke of burning cedar is attracting the good spirits and eliminate negative energies.
Smudges may help clear the air, scientists have observed that sage can clear up to 94 percent of airborne bacteria and disinfect the air. Also, when sage is burned, it releases negative ions, which is linked to putting people into a positive mood. 
Smudging requires simple ingredients like matches, smudging herbs, and a smudging bowl. Before you start, remember to open a door or window, because the unwanted energy you are trying to clear must have a pathway to get out. First, light one end of your smudge, allowing it to catch fire and burn for several seconds. Then gently blow on the lit end - the smudge will begin to glow and smoke. Lay the smudge on a heatproof bowl to catch the ashes as it burns.