By the time you receive your crystals , they have been through many hands and places and due to their energetic nature the crystal holds on to every energy pattern it come in contact with. With that being said you want to make sure you are properly cleaning your crystals before using them. Personally you should clean your crystals as soon as you get them and at least once a week. There are several methods for cleaning crystals.
Light a bundle of sage, lavender, sweetgrass, and cedar. Then hold the crystals in th stream of smoke to cleanse them. You can also cleanse them with smoke from n incense.
If you have some type of energy healing ability (like reiki), you can cleanse the crystals using that energy.
Nonporous crystals, like quartz and amethyst, can be soaked in a saltwater solution. Submerge your crystals in the salt water for about an hour, you might want to change the time depending on the size, then rinse them and pat them dry. You can use sea salt or Himalayan salt but not table salt! So remember that!!! Also this method can not be used on porous crystals like selenite, desert rose, or gypsum because the salt will damage the stone. So make sure you check which stones you have before using this method.
QUARTZ CLUSTERS OR GEDOES
If you happen to have a large cluster made out of Quartz stones like amethyst or clear quartz, you can place your smaller crystals in the cavity for 24 hours to cleanse them.