Cleansing can be done in many ways. Any or all of the elements can be used. You can place it in the light of the moon for a cycle or smudge it with white sage. Carnelian is a stone that does not pick up negativity and is often used to cleanse tools and other stones.
If you would like to perform a simple cleansing ritual you will need:
A censor with incense or incense stick/cone ( Frankincense or White Sage ). A white candle and something to light it with A bowl of water. A bowl of salt
Cast your circle and call the quarters. Light the candle and incense. Take your tool or crystal and pass it through the smoke from the incense saying, “Element of Air, negative energies take flight." Pass it through the flame saying, "Element of Fire, burn away the darkness of the night." Sprinkle with water saying, "Element of Water, wash negativity away." Sprinkle with salt saying, "Element of Earth, draw out what stands in my way.”
Now hold the tool or crystal before you and say: “All the elements here combine, from negativity now is free; This sacred object that is mine, fill with light, so mote it be!"
Release the quarters and close the circle. Your new tool is now ready to be used!
Spend some time with it close to you to fill it with your energy and become attuned to it. You can also charge it for a specific purpose.