We also use MaOH, but never reuse a tissue. One tissue, one drop, one 
wipe. If using your fingers to hold/fold the tissue, you need to be 
gloved to stop finger grease entering the tissue. The test on a corner 
as suggested is a good idea but so far I've never seen a problem with MeOH.

Cheers


> I usually clean coated optics with a single swipe of methanol on a
> lens tissue.  Take a lens tissue and fold it a few times, put a drop
> or two of methanol on it, and do a single swipe across the surface.
> If the fingerprint refuses to come off, refold the tissue you just
> used to expose a clean surface, add another drop of methanol and swipe
> again.  If you are uncertain that your particular coatings are
> Methanol-compatible then test a tiny corner of the optic first!
> Also, make sure to use 'molecular grade' or ultra-high purity
> methanol, as standard stuff contains things that will contaminate your
> optic.
>
> Craig
>
>
> On Wed, Oct 7, 2009 at 11:42 AM, Carl Boswell
> <[log in to unmask]> wrote:
>   
>> Hi all,
>> I have some emission filters with dust that will not blow off, and one with
>> an obvious fingerprint, all of which show up as blurry smutz in the image. I
>> appreciate the need for caution when cleaning filters with soft coatings;
>> e.g. no organic solvents, no touching, etc.  But what about a simple soak in
>> dilute soap and water, followed by dH2O rinse?  Or, will a polymerizing
>> cleaners, such as Photonic's First Contact work?  Obviously there is a
>> solvent in this to keep the material liquid until applied.
>>
>> Thanks,
>>
>> c
>>
>> Carl A. Boswell, Ph.D.
>> Molecular and Cellular Biology
>> University of Arizona
>> 520-954-7053
>> FAX 520-621-3709
>>
>>