The short version: “cleansing” a crystal is part practical cleaning, part tradition. Here are the common methods and, importantly, which stones to keep dry.
Water rinse — a quick rinse and soft cloth for most quartz-family stones. Skip the water-sensitive ones — selenite, malachite, halite, and other soft or soluble minerals can dull or dissolve.
Smoke — many people pass a stone through incense or dried-herb smoke.
Selenite plate — resting stones on a selenite slab is a popular, dry method.
Moonlight — leaving stones out overnight under a full moon is a long-standing ritual.
Sound — a bell or singing bowl near the stones.
These are care-and-tradition rituals, not requirements. See our selenite for the plate method, or visit a Sedona shop.