There is ANOTHER WAY to take off and install handguard clips without hurting the handguard:
Tools needed: 18 ga. soft iron wire (like used for safety wiring bolts), bench vise, and vise-grip pliers
Procedure:
1. Thread a 12" piece of the iron wire through each holes in the handguard clip. Twist the end of the wire around itself so it won't slip out of the hole in the clip.
2. Clamp the loose end of one wire in the bench vise
3. Attach the vise-grip pliers to the end of the other wire
4. Pull on the vise-grips to spread the clip, and while holding the clip spread, "roll" the handguard out of the clip
5. Reverse process to reinstall
I actually prefer this method to the special handguard pliers, as there is no way to "slip" with this method, as you can do so with the handguard pliers.