One method ,heat the nock until it's a round glob of plastic with porosity holes and while it's still warm (not dripping hot for safety's sake)use a box cutter or sharp knife sticking the tip straight down into the nock until you hit the taper,keeping pressure on the knife so you'll follow the taper cut away from the arrow tip and yourself,on 2 sides of the nock 180 degrees apart this will cool quick and let you basically unwrap the nock from the taper,good ventilation is suggesteg,GOOD LUCK if you try it this way.