Palo Santo (which means holy wood) smudging sticks come from a tree from South America (predominantly Peru) and are used to cleanse and charge your crystals, room or area. The tree must have been dead for 4 - 7 years before harvesting. The smell that Palo Santo emits when lit is a mixture of pine, mint and lemon. What is great about this, is that it only removes negative energy and leaves the positive energy.
To use - light the end and allow it to smoulder. Place in a fireproof bowl and run your crystals through the smoke. Remember to use by an open window to allow the negative energy to leave. If using to cleanse a room, waft the smoke into all four corners of the room. Ensure you are using a fireproof bowl to catch the ashes as this can be a fire hazard.