Home Repair is Easy: Replacing Push Button Mechansim - Just use a little piece of tape (preferably black electrical tape because it's stretchy) to grip the rear mechanism base on your current pen and unscrew it from the barrel. (counter clockwise) Next screw in the new mechanism (clockwise) and then use another piece of tape to grip the mechanism base so it's snug in the barrel. (then pull tape off) **NOTE ALL PENS SINCE - APRIL 1, 2006 have the improved (stronger) push button mechanism. Replacing Nose Tip - Grip the nose tip and unscrew then screw in the new nose tip. **NOTE ALL PENS SINCE - APRIL 1, 2005 have the new stronger Stainless Steel Nose Tips. (The Stainless Steel Nose Tips are identifiable by the 'USA' engraved on the side.) Replacing Clip - Snap the Clip over the Barrel Replacing Spring - Push small end of spring onto Parker Gel Style Refill First (it only works this way)