Everywhere you look there are different rules for cleansing your stones ... sunlight for 3 days ... under the light of a full moon ... giving them a salt water bath, even burying them in the ground for 3 days. I personally like keeping them in a dish with a Selenite and a Kyanite as my favorite cleaning style and in all honesty the easiest from my perspective.
Selenite is a cleanser and a clearer of environments and energy fields. It works best if kept in the entry ways of your home or work spaces as it does not allow negativity to pass and can help to wash the day's stresses away. This stone does not like water, so please don't wash it. You can however, smudge it with sage smoke or charge it in the light of the moon.
Kyanite also cleanses and clears with the added benefit of not allowing negativity to glom onto you and transmutes any negativity into light, and returns it to source. I personally always have one of these stones on me at all times and have found that this is a stone that every empath should carry to reduce the amount of fatigue associated to whatever environment we find ourselves in.
Another stone in my cleansing arsenal is Citrine ... bringing the power of the sun to the table... or the dish if you will. Citrine also naturally removes negativity by transmuting it into light source energy and can also charge the stones around it.
In my opinion a great rule of thumb when questioning how to clean your stones and crystals look at the makeup of them ... if its porous like lava rock, it can be washed under warm running water, and if you use it for aroma therapy you definitely want to wash the old oils out before applying new scents. If the stone looks fibrous like Selenite, keep it away from water as it will fracture; you could choose smudge or sun as the cleaner. For polished stones you are safe with water, but for the lustrous stones a quick rinse is all you need... no 3 day bath for those like Moonstone or Opal.
We forget that the stones and crystals we cherish came from the earth and are in most cases thousands of years older than we are. They have been through so much in the very creation of them, then the harvesting, processing and polishing. We cradle them reverently in our hands when selecting them and gasp at the thought of dropping them ... these beautiful rocks of ours.