Can someone advise me (for or against!) cleaning the mirror, lenses and CRT faces in a Mitsubishi WS59909 rear-projection set? Best plan for opening up the box, how to clean, what to watch out for, etc? Also, is the optical focus something that is adjustable in these sets? I've had the TV for about 5 years and it's been trouble-free, but I feel that there must be dust and stuff inside that should come out. Thanks!