Lay your bolt on the floor with the handle to the left and bolthead to the right. Place your right foot firmly on the bolt body and rotate the bolt handle away from you until it is against the floor. Insert allen wrench at about a 45 degree angle and stomp on it like it was an armored cockroach. Don't play with it just stomp the poop out of it, standing won't do it a lot of times. It will make a loud pop and it is loose. That's all there is to it. Keep it OUT of the vise. Too much chance of it turning and gouging the bolt body.