I have two pin locks, and the rest are ball locks.
Like Bobby I just hit the GAS post poppet with a screwdriver. Press it down and the pressure is released.
Two very important notes.
1. Never fill up the keg to where it is over the gas in tube. Think beer showers.
2. Never mix up the gas and beer post. It's not funny with a dark beer with white paint around.
I use duck tape to mark the gas in post on the holders handles.
It helps when I am working in keggerator with very poor lighting, or when I have enjoyed a little to much.