Use an exacto knife and slowly dig around the edges until the knife fits in somewhere. What I do is push on the four corners repeatedly. Don't push too hard if you don't want to scratch the paint. Once the knife is in, you can wiggle it back and forth (make sure you don't break the knife into your eye or something) until the knife is loose in the groove there. This will take a while... so be very patient. You will get to a point where the exacto knife will be too small, so simply grab a 'thicker' knife. I don't mean a bigger knife perhaps, but something like a survival knife would do because these things are nice and thick. Now all you have to do is pull the cap out with this big knife using the same procedure but with a little more force. Distribute the force across the 4 edges and you'll get a clean rip. Unlike the regular leadlights, the Atlasnova lasers' endcap is not attached to the laser module. Taking the endcap off will leave the module in place and allow you to clean it very easily!
Hope that helps. Don't hesitate to ask further questions;
DDL