The good news is that they do actually come off. The bad news is that the extremely high levels of mojo emitted from these amps tend to cement the jewel light in place. Please follow instructions below.
1. Acquire paper towel or rubber 'jar lid' opener. Ask if you don't know what either of these items are.
2. Address the amp from the front, explaining what you're about to do is really for the amps benefit. It wants to look fly.
3. Grip the metal edges of the jewel light with your chosen item from step 1.
4. Twist counterclockwise (from your reference position of addressing the amp from the front), with total disregard for what your fingers will look like after the process is completed.
5. If unsuccessful, invite a friend over to do it for you. Be warned...this friend will succeed where you fail, and that included tappin your girl. So I recommend you try hard.
Strat.