That's basically what I do. I spend a significant amount of time at my
optical dealer part time job restoring both vintage optical items and traded
in newer stuff. Often they have had some serious use or time since they were
last cleaned. I've tried alcohol and it can't get the really stubborn things
that acetone seems to be able to get. Of course unless you are collecting
camera gear from 30+ years ago like I do also you aren't going to find
really stubborn problems on the more recent stuff.
Kent Gittings

-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED]]On Behalf Of Rob Studdert
Sent: Thursday, November 01, 2001 7:11 PM
To: [EMAIL PROTECTED]
Subject: RE: Lens cleaning


On 1 Nov 2001, at 14:11, Kent Gittings wrote:

> Acetone is the best lens cleaner. Make sure you get it pure not something
> like nail polish remover. That and Q-tips will get anything off a lens
> without harming the coatings. Acetone will require you to rub it with a
> clean dry Q-tip if the element is dirty enough so that the acetone  leaves
a
> streak when you use the fluid. Kent Gittings

I'm with kent here, but I use Chemtronics Low Lint Cotton Tips which are
like
a long single ended Q-tip with a wooden shaft. The are specifically designed
to clean optical assemblies and other equipment, I bought 1000 (in packs of
100) for the equivalent of about US$30, not bad value. I have used acetone
however it can cause damage to plastic or painted surfaces so I usually use
pure isopropyl alcohol purchased at a local pharmacy. I have found the
alcohol to be little less problematic with plastics but it can still affect
some
inks but both solvents seem to have similar capabilities WRT lens cleaning.

The method that I use is to initially saturate a swab and paint over the
whole
glass area to be cleaned then I get a dry swab and dry off the lens, you
will
most probably be able to see streaks on the glass, these are contaminants
and are usually greasy so every step I use a new swab and even if it looks
clean I put it aside now relegated to less some other demanding cleaning
task in its second life.

I have found that often there is a build up of greasy gunk in the interface
between the glass and the edge of the lens barrel, a lens might look clean
then as the swab comes from the edge it will draw a great line across the
coating, once the swab has contaminants on it it will leave streaks. The
most effective method to finish the surface is to use the swab on its edge
and gently roll it so that the remaining contaminants are dispersed across
its
surface rather than concentrated in one area.

Well I didn't intend to write this much but there it is, if you persist you
will
have a virtually absolutely clean surface and you can re-assemble your lens
knowing that there isn't any gunk inside (or outside), you might go through
10 or 20 swabs though. The last point is that when doing lens repair it is a
good thing to have compressed air or nitrogen handy to blow the dust out of
the lens before it is re-assembled :-)

Cheers,

Rob Studdert
HURSTVILLE AUSTRALIA
Tel +61-2-9554-4110
UTC(GMT)  +10 Hours
[EMAIL PROTECTED]
http://www.ozemail.com.au/~distudio/publications.html
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