What's up realcarlos purging is when you put the oil in a vacuum desiccator chamber and suck all the air out of the chamber which in turn purges the oil of all air and left over butane. Which also in turn make the oil very stable and brings the taste right out I use the food saver vacuum jars with a brake bleeding hand pump. I think purging is the most important part if you don't purge you will be smoking the left over butane and the oil is just to hard to handle when it hasn't been stabilized from purging. Next run I do I will do a tutorial on how to safely and properly make high quality BHO!!!!!