[NQLD_Newby]

I have cleaned the primary mirror on my 4.5" reflector a couple of times using the exact method described in the article you have mentioned and have found absolutely no damage was done, and perhaps because of the small size, (less light gathering ability), I actually did noticed a huge increase in performance. I haven't had my 12" long enough to gather enough marks to do it yet, but I have no reservations what so ever, and can say that when the time comes I will be doing it also.

On your other point regarding the distilled/demineralized water difference. My lovely wife runs all drinking water through one of those filter jugs. I used it to clean and rinse my mirror (not tap water as mentioned above), and as stated earlier have seen no evidence of damage. I can't rememebr what the article says about tap water, but I was concerned regarding the minerals and chemicals added at the water treatment plant, so chose to use the demineralized water for all stages, just to be safe. Hope this helps.