[Leica] Sensor cleaning revisited

[hopsternew at gmail.com (Geoff Hopkinson)]

I had a recent exchnge on and off list regarding cleaning the M9 sensor.
When I just cleaned mine ( which has not had heavy use), I was dismayed to
find that I had persistent streaks, some of which looked alarmingly like
fine scratches.
I was confident that I had been careful. I used the Arctic butterfly brush
first to remove any loose dust and then did a careful wet pass with Visible
Dust Plus. I only had 1.3x size swabs.
The streaks remained after 3 separate cleaning cycles with new swabs each
time.
I repeated this all with the Dust Aid kit which uses swabs that you need to
manually wind around the spatula and their fluid. Same result. My Leica
dealer repeated this, same result.
We could not budge the easily visible streaks although they were completely
undetectable on test images at high magnification on a monitor.

Today I repeated the dry clean folowed by a wet clean with the Eclipse type
3 (size) swab and their fluid. They no longer consider the E2 fluid
necessary for tin oxide sensors and recommend their standard fluid for every
sensor.
A single pass in each direction completely removed every trace of the
streaks and I am a happy camper. I believe that the streaks I had were
either traces of oil, possibly from the swab touching the surrounds of the
sensor (shutter lubricant??), drying marks from the fluids used (qty?) or a
combination of both.

I note that the Eclipse fluid contains methanol.
Visible Dust fluid does not and they state that methanol can damage the seal
of the covering bonded to the sensor.
Leica recommends isopropyl alcohol.
In any event I wanted to report my experiences. I'm sure that others will
have had different experiences and views. Incidentally the Eclipse swabs
actually cost even more here than the Visible Dust products so that should
please those who considered I was skimping by trying the Dust aid swabs when
my Visible Dust ones (M8 size) ran out!

Cheers
Geoff
http://www.pbase.com/hoppyman