Man i allways like buy a fresh 1/8th of weed and grind it all up straight away, then transfer it staight back to my weed bag. I is space consuming, so's all th weed fits comfortably in my tin, and Certainly in my experience i haven't noticed that it has ever taken any potency outta the weed at all! LOL i mean basically i grind my weed all the time, and i certainly dont have a problem gettin high!