[Leica] 21mm M Biogon question

[glehrer at san.rr.com (Jerry Lehrer)]

Sonny und Mark und Akhil,

I have found that an ultrasonic cleaner is the best way to clean really 
dirty filters.  O f course do not
use it with polarizing or other cemented or laminated filters.  ONLY 
solid glass filters.  They will not
adversely effect coatings, even Inconel anti-IR coatings.

Jerry


Sonny Carter wrote:
> On Thu, Jun 26, 2008 at 9:21 AM, A. Lal <alal@duke.poly.edu> wrote:
>
>   
>> Mark,
>>   Then there was the 67 mm UVa that was mounted on an 80 Summilux and was
>> smudged by a toddler's [not mine :-) ] ice cream cone. No amount of 
>> cleaning
>> could clear up the residue and I ended up discarding it.
>>     
>
>
> You probably could have cleaned the lens.  I can't imagine not being able 
> to
> clean ice cream off a filter.  I'm a frequent user of ice cream in various
> containers, including crystal.  I'll try some in my schott egg coddler
> though to see if it affects that Zeiss glass.  ;-)
>
>
>
>