The Doctors Thrash had used charcoal in a hospital setting during their training, for poison control.  It was a miracle substance, that saved lives by taking up poisons (like drug overdoses) powerfully, leaving the physiology without harmful effect.  After seeing more research on activated charcoal in the 1970s, the Thrashes put together some of those studies along with their own experiences into a book they titled, Rx: Charcoal.  When people asked where they could obtain charcoal, it seemed there was no good supply for a quality--but inexpensive--charcoal powder for household use.  Large quantities were needed for poultices, charcoal baths, and other household applications, such as deodorizing and removing clorine from drinking water.  We decided to start supplying it ourselves, and began carefully filling each jar by hand.  That was in 1983, and today, we still take old-fashioned, steam activated wood charcoal and carefully fill our jars by hand.