There are probably as many ways to clear crystals as there are people, or crystals for that matter. I recommend that you clear any new crystal as soon as you get it home. When you first get a new crystal it's a good idea to cleanse it to clear any energy left from people handling it in the store or whatnot. Clearing the crystal is quite similar to the personal centering and clearing one does before embarking upon some new facet of their path. That way it is all clear for attunement and programming. Here are a variety of ways I have used to clear crystals. As with all things, go with what feels right. I highly recommend creating your own personal clearing ritual.Some stone people don't do well with some cleansing methods; halite dissolves in water, for instance.