Spiral Lock Piston Pin Retainers

[ElephantKiller]

Anybody know a good way to remove the spiral lock piston pin retainers without damaging the piston or the pin? I know there is a tool out there, but it's 100 bucks.

 

[388dart]

All I've ever used is an Awl (or similiar sharp pointed object) and small flat screw driver - and time and patience.