Use a thin piece of plastic, spudger, or fingernail (if you have them) to lift up the edge of the grip, and pull up slowly.

Repeat for the other two grips

The large one on the battery-side is the easiest to start with. This is required to remove the front & back panels

The small one on the back is a bit difficult to get started, but not really difficult to remove.

The one on the AV panel will be easier if you open up the AV port cover.

Remove the adhesive like you would rubber cement, just rub your finger against it, it will come off.

Optionally throw the balled up adhesive at people pretending its a booger :)