Now tell your friend to repeat the light invocation and again measure the energy field. If the measurement increases after the light invocation beyond the original measurement, two things are possible. First the light invocation does, indeed clear out the negative emotions. Second, the light invocation also increases the overall energy field. Cleansing is a process of reducing the negative emotional energy level to the crystal to the point where the emotional energy can no longer affect you.
Salt is the recommended method.
Bury the crystal in either dry salt or submerged in a saline solution of cup sea salt to one gallon of water for at least one day. Grounding returns you to your connection to Mother Earth. Too much energy input, whether it is environmental or emotional, can cause you to separate from your body. You might experience a feeling of disorientation, confusion, and separation. Ground yourself by closely in tune with your crystal.