If you're starting to get a lot of white lines in your retinal images, try these steps before calling out for service. This will only take you about 10 minutes and can save you a thousand dollars or more. THIS MAY VOID YOUR WARRANTY AND MAY DAMAGE YOUR MIRRORS. BE CAREFUL AND USE COMMON SENSE.
Step 1: Remove 3 Screws, Cables, and Take Back Off
You will need a #3 triangle bit. I just bought a cheap set from Amazon. They come off with only about 1/2 turn to the left. They will not fall as they are attached to the chassis. The back panel easily lifts up and off the chassis.
Step 2: Remove Top Front Housing Panel
To remove the front top housing panel, push these tabs with your thumbs outwards. The front panel will come lose and is easily removed upwards.
Step 3: VERY GENTLY Clean the Mirrors
Clean all of the surfaces you see outlined in red. The one long mirror on the left is green in the second photo for clarity but it is the same surface. If it is very dusty, I would use a can of compressed air, but be very careful. Hold it upright and use gentle bursts of air. Do not turn the can upside down or sideways as the liquid propellant can come out and damage the mirror. I would only use a lens cloth and gently clean the mirrors and surfaces. Our main mirror was very dirty on the bottom with something I could not rub off so I did use some lens cleaning spray onto the cloth first. Once you are done cleaning and polishing the mirrors, place the front panel back and snap it in place. Then place the back panel and tighten the screws.