Re: cleaning
I agree with dano about the reflectors. Don't touch them with anything. Maybe that canned air used for spray cleaning computer parts/electronics would be ok, but I've never used it, so I'm not completely sure.
As for lenses, I usually use rubbing alcohol on a cotton swab on the inside. I'm a little rougher on the outside, since whatever I use won't be as hard on the lens as the dust, dirt, rubbing fabric from my pocket or holster. Mostly I can just rinse the outside lens with water while it's on the light, as long as the light is water resistant.