Crystals and metals are favorite jewelry items for people who work with energy. These materials pick up energy from the people wearing them and hold it, bringing that energy into the wearer's life. People who work with energy often charge their jewelry with a specific intention or attune it to themselves. If you are wearing second-hand jewelry, the previous owner may have charged or attuned it, or it may have picked up negative vibrations. There are many ways to cleanse your jewelry and remove attunements that don't work for you.
Bury your jewelry in the earth. Soil grounds and cleanses energy. Leave it there for 24 hours before retrieving it.
Fill a container with salt and place the jewelry in it overnight. Only do this if salt will not scratch or damage the material. Like earth, salt grounds old energy.
Submerge the jewelry in fresh, running water for several hours. The water will carry away the old attunement. Submerging jewelry in saltwater also works.
Smudge your jewelry with white sage. Light a bundle of sage incense, and hold the jewelry in the smoke for several minutes. Sage dissipates energy.