There are various alternative ways to cleanse crystals other than using the full moon's energy. Some methods include:
Running water: Hold your crystals under running water to cleanse them.
Smudging: Use sage or other herbs to smudge your crystals, which helps to remove negative energy.
Sunlight: Placing your crystals in direct sunlight for a few hours is another way to charge and cleanse them.
Earth burying: Bury your crystals in the earth for a period to allow the soil to cleanse and recharge them.
Sound therapy: Use tuning forks or singing bowls to cleanse your crystals with sound vibrations.