Many ways to do it, pickle forks work but tend to kill the boot. Hitting the side of the lower control arm will generally get it out without hurting the boot. There is no popping back in, just torque it down and put the cotter pin back in. If the cotter pin happens to not line up with one of the slots on the castle nut over torque it to get it to line up, don't undertorque it since it can be too loose and cause other problems but it should line up right back where it was.
Ryan