Paul, an explanation....
For those who haven't seen it, you must visit this thread...
http://www.rangefinderforum.com/forums/showthread.php?t=117591
Leica makes very good cameras. I was so impressed by the M9-P and Noctilux combination that I went back to the store and bought several more Leica cameras. I think they will make me a better photographer.
One thing that I found disappointing is that the Leica M8 and Leica M9-P cameras and Noctilux and Elmarit lenses do not have self-cleaning sensors. I asked a friend of mine, a fellow dentist, what technique he prefers for cleaning his sensors. He showed me this very useful technique. It is very automatic. I think it will make me a better photographer.
You simply place the camera into an automatic dishwasher, preferably from a manufacturer such as Bosch. (The kind salesman at the photographic store told me that it's best not mix products from Germany with those from other countries.) Then, and this part is very important, especially, if like me, you want to be a better photographer; using the wash cycle selector lever, button or knob on your German dishwasher, very carefully set the cycle to number 2. That seems to work best.
My other disappointment with the additional Leica cameras that I purchased (by the way, they must be very good owing to the fact that they are quite expensive ... even these very old ones for some reason; but I think they will make me a better photographer) is that they do not seem to have sensors that can be cleaned. However, my friend still said they could benefit somehow from a good cleaning, so I've also carefully loaded them into the nice Robert Bosch dishwasher.
Okay, then, now we're ready to clean our sensor. Don't forget: setting no. 2 works best.