Start by slowly pushing the ends of the two halves down and out of the ir ring shield, and once you are to a point like this, you'll want to push the shield down on the back, while prying the front side up

On the left controller, there is an extension to the plastic near the trigger, that makes it alot harder to remove the shield. I ended up needing to cut some of it off and pull extremely hard, but ended up still breaking a little rubber dampener inside the trigger, that's there to reduce the sound of using the trigger.

Afterwards, the shield should come off

Feel free to celebrate a little, as you just completed the hardest steps!

If desired, you can put a battery back in and test the controller to see if tracking still works, to ensure no damage was caused to the ribbon cable in the process.