I personally believe that others touching your crystal could add to the crystal attributes. After all each of us have strengths and weaknesses and those combined could be very beneficial. The key here is chosing those people very carefully. Even the bad when cleansed could leave whatever good each person had within them. The best cleansing is done by placing the crystal to be cleansed on top of a Quartz cluster in the sun from early evening though the night, the next day, ending the process after a complete 24 hour cycle.
Crystals are attuned to the cycles of the earth and natural infra frequencies.
I find it hard to do that when I won't even drink the water coming out of our pipes, but have to drink bottled spring water. But this time does give a private time with the crystal. Keeping a 'Real' Boji stone next to the crystal is also a wonderful way of keeping a crystal cleansed. I believe in only doing it when they are touched by someone that I wouldn't want to touch me. You do not have to agree with anything here, but it would be a shame if you do not share your views with everyone.