A method for post processing oil extracted from cannabis comprises the steps of placing the oil into a pressure rated vessel, adding a first predetermined quantity of liquid Butane, sealing the pressure rated vessel shut, and heating the pressure rated vessel to a first predetermined temperature for a first predetermined time. The steps further comprise cooling the pressure rated vessel, releasing pressure from the pressure rated vessel, transferring the oil from the pressure rated vessel to another container, and vacuum oven purging the oil under a first predetermined level of vacuum at a second predetermined temperature for a second predetermined period of time.