This used to be on the USDOJ website, written by a USDA scientist, Mary Aycock. This was field work, literally. Opium was dissolved in hot water, making your basic opium tea. Picture an Afgan field, 55 gallon drum over a fire, that simple. To this is added limestone, powder is best. Most everything will precipitate out, leaving calcium morphinate and codeine in solution. Pour or siphon off through a cloth filter. Add ammonium chloride. Evaporate. There is the morphine base, as always tainted with codeine. Ready for the lab pickup.
