These are just a few of the dozens of types of ways to cleans negative and excess energy from your stones. Enjoy.
~ Visualization ~
This method usually entails holding your crystal in your hand (open or closed) and then you can go through a basic meditation in which you envision all the dirt and stickiness flowing away from the crystal. You can also add a bright white healing presence surrounding your crystal, watch as all the negative tar seeps out from the crystal and is dissipated and cleaned by the white light. Then once all of the filth is gone admire your beautiful sparkling friend and meet them again for the first time.
~ Breath ~
This can be a fun method! You hold your Gem in your hands close to your mouth and imagine all the extra energy flowing out of the crystal and into the wind as you blow onto the Gem. It is kind of like blowing on a dandelion puff and making a wish. This is a method you can use as often as several times a day... Just be careful, repeated use of this method in a short period of time can lead to lightheadedness and a silly feeling in your head.
~ Water ~
You can give your stone a good ol' fashion bath, soak it in a bowl of water over night with a possible scrub down as well. If soaking your stone doesn't want to take a bath, it may very well like a shower. Run some cool or hot water (depending on it's preference) and place your beauty underneath the water for a bit, literally washing away the funk.
~ Sun ~
Everyone can appreciate a nice sunny day, so why keep your crystals in the dark. Leaying your crystals out in the sun for a day to soak up some rays can bake away all the excess baggage they are carrying around. (WARNING! Amethyst, Citrine, Smokey Quartz, Fluorite, and any other translucent colored crystals and stones can be faded by the sun! You will want to try a different cleansing method for these!)
~ Moon ~
If you'd rather not put a particular stone in the direct sunlight, try the bright glow of a full moon for a night; Any moonlight will do, however the Full Moon has meanings all its own.) The Moon is a powerful tool in transmutation and it can easily suck the yuck out of your friends heart and return it to a state of pure bliss.
~ Earth ~
Until I actually tried this method I was skeptical... I was told to bury my stones in a shallow grave under a few inches of dirt and leave then for about 3 days. I tell you, returning my crystals to the earth for a short vacation worked wonders! When it's time to bring them back to the surface make sure you wash them gently with water, unless you'd like them to hold on to the rustic film of dirt for a bit.
~ Smoke ~
One classic way to rid any energy field of anything unnecessary is to smudge it with Smoke. Take a leaf of Dried Sage, light it and blow out the flame. The leaf should be smoking, now surround the Crystal with the smoke and send the extra "stuff" away. Sometimes when I smudge I can get really into it, and I will vocally talk to the negativity and tell it to "shoo" while making the shoo-ing motion with my hands :) Other Herbs commonly used for their purification abilities are Frankincense, Cedar and Sandalwood.
~ Flames ~
You must take great precautions when using flames on Crystals and Stones, they are fragile when it comes to heat. Flames however are an excellent way to keep your stones fresh and clear. One safe-ish way to do this cleaning is to light a candle and gently run your crystal above the apex of the flames several times. It should not be close enough that the flame leaves soot on the stone because that can cause your crystal to fracture of crack.
~ Salt ~
Salt, preferably Sea Salt (for it's natural mineral content, lack of additives and both metaphysical and physical properties) can be used to cleanse your stones, you may want to consider this method if your stone is desperately in need of some help as a salt cleanse can be rather harsh on delicate or softer stones. On to the details... One way to do this is to fill a bowl with salt and bury your stone completely in the center, then leave it for 1-3 days. You can also give your friend a gentler salt water bath, mixing warm water with salt and placing the stone in there for an overnight soak. Adjust the saltiness depending on the severity of the clog, and make sure to rinse off the stone afterwards to remove the salt residue. Like I said, this method can be harsh, please take into consideration the type of stones you cleanse with salt, if you have any concerns or questions be sure to ask!