On Tue, 05 Mar 2002 09:27:32 GMT, "Toby" wrote:

>As a working cameraman out in the field every day with 127 mm filters I have
>a different piece of advice. The easy way. Breathe on the filter so that a
>fine condensation forms on the glass (condensation from the breath is almost
>pure water). Then wipe off with lens tissue or microfiber cloth. Kleenex
>will work in a pinch but will leave lots of lint. The problem with using any
>kind of liquid is that when it evaportes it will leave streaks
>behind--either because it leaves a residue or because junk from the air gets
>mixed up in there. If you use a moistened tissue or cloth it leaves a thick
>film of moisture on the glass surface and you have to keep rubbing it until
>it is gone. This means more chance of scratching the glass. If you breathe
>on the glass you can even "spot clean" it. The amount of moisture is enough
>to loosen whatever is on the surface (apart from heavy grease) but little
>enough to be completely dried in one swipe or two of the cloth. I've been
>doing this for about 30 years with all kinds of coated lenses and front
>surface mirrors and have always had much better luck with this technique
>than with all those fancy lens cleaning compounds like ROR, etc. The
>absolute very best is freon but it is now banned, with good reason. Breath
>is the second best, except in very hot dry climes where you cannot get any
>condensation to form on the glass.

I agree with this, as the "second level" of cleaning, after
simply blowing air on the surface with a large air bulb,
and before resorting to other options mentioned in my post
above (for going after stubborn grease). I would add that if
the glass surface is multicoated, it is best to breath up
toward the down-facing surface to avoid spit drops that
make hard-to-remove "silvery" spots on the glass...