Mirror Cage/Chamber Cleaning - This is not a sensor cleaning technique but a preventive measure. Some cameras need it worse than others, over all it is a good idea for all camera models on an occasional basis. This also helps keep the stray lubricants from contaminating a brush when using the brush method. There are currently 2 major methods of accomplishing this task, both of which use a foam swab (DO NOT attempt this with a cotton or polyester swab). We said methods but what we really meant are chemicals, one being ChamberClean™* by VisibleDust and the second being Eclipse™ by Photographic Solutions with the ChamberSwab™ by The Dust Patrol. Both work the same way and that is that you put a couple of drops of the chemical on the foam swab and you clean the 3 walls of the mirror cage/chamber and the bottom side of the mirror.
Items needed to complete this task: foam swab, cleaner and your Digital SLR Camera Body.
Use the “mirror lock-up” function of your camera or manually lift up your mirror exposing the 3 walls of the mirror cage/chamber, the bottom side of the mirror, and the shutter blades.
To manually lift up the Mirror, fire the camera a time or two at a slow shutter speed while looking into the mirror cage so that you can see how it is hinged at the back and goes up and down. The mirror is held down by springs and can be lifted up with little to no effort with a fingernail or the handle end of the foam swab.
Place 2-4 drops of cleaner on the foam tip of the foam swab.
With the foam portion of the foam swab, wipe the 3 walls of the mirror chamber and the bottom side of the mirror. Wipe the lens mount and face of the mirror cage. DO NOT touch the Focusing Screen or the Shutter Blades.
If you have to re-wet the foam swab, make sure that it is never sopping wet (cleaner dripping off the tip) as you never want to leave puddles behind.
* At this time, we can not recommend ChamberClean™ due to possible safety issues with it's manufacturer's unwillingness to supply MSDS sheets.