Clear a jewel
Since you also have to remove the chrome XBOX lettering you can use:
Brake Cleaner, oven cleaner, paintthinner, alcohol or any other chemical that wont melt or cloud up the jewel (but NEVER use acetone)
Mask of as much of the jewel as possible but allowing you to get paint into the now empty XBOX letters and "fill" them with the color of your choice (second coat might be needed to fill them)
Once the paint has dryed
Remove the masking tape
Sand the excess paint of (XBOX jewel sanding and polishing)
Now you´re jewel should look like this (if you chose green) and you can stop now and light up the jewel with a CC
Or you can mask of the front of the jewel and give the jewel a nice background color
When its dry you´re done
