Rich, I would not simply use PhotoFlo. Here is the best way to clean optical surfaces. I have done it at least twice and it's wonderful. http://www.arksky.org/asoclean.htm -- Joe From: Richard Tenney via Utah-Astronomy <utah-astronomy@mailman.xmission.com> To: Utah Astronomy <utah-astronomy@mailman.xmission.com>; UVAA <uvaa@mailman.xmission.com> Sent: Thursday, January 1, 2015 11:46 PM Subject: [Utah-astronomy] Telescope mirror cleaning Someone recently posted the following in the Criterion Dynascope email forum re: mirror cleaning, that I thought some of you might find useful/interesting. I had never heard of this stuff (and it's probably overkill, but what the heck)... "The best possible soap is Kodak PhotoFlo, which was designed as a last rinse for photographic film. It is the essence of all dish soaps, minus anything else. Still available from B&H and Adorama. Useful anytime you want to avoid water spots, like clear shower panels. It has to be diluted in distilled water 200:1 so a pint goes forever." FWIW,/Rich _______________________________________________ Utah-Astronomy mailing list http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Send messages to the list to Utah-Astronomy@mailman.xmission.com The Utah-Astronomy mailing list is not affiliated with any astronomy club. To unsubscribe go to: http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Then enter your email address in the space provided and click on "Unsubscribe or edit options".