Keef or Kif is like weed powder, some grinders have a screen on the bottom and a small container under that so when you grind your herb the THC crystals are collected and can be used to get you super stoned, just put a small bud in the bottom of your bowl and sprinkle kif on it until the bowl is full and smoke that (be sure not to touch it to the flame as THC will be destroyed if you torch the bowl.