From personal experience, save the duff. Also save your stems! Grind stems up, mix with duff, then do what you want to do. Use oil, butter, or milk if you're going to cook. Use alcohol if you want QWISO hash, or butane if you want honey oil. Or you could make Green Dragon with it. I've done all of the above and have had pleasant results each time. I use a Vapolution by the way. To me its like letting nothing go to waste, if you have stoner friends, ask them to set you some stems aside or duff if they have it. You'd be suprised. Every few days somone is calling me, "Hey man I have like a 1/4 worth of some stems and duff if you want it". It all adds up and the more you use, the better the results.