What brush to use and not to use is a different subject, what I have here is true for all brushses, good or bad.
PRECAUTION: The #1 issue consumers are having with the "Brush Method" is the brush leaving smear marks on their sensor. This is caused by a contaminated brush and there are 3 main ways a brush becomes contaminated:
By Canned Air. I have yet to see any canned air that is contaminant free 100% of the time and this is why we (
www.cleaningdigitalcameras.com) do NOT recommend any type or brand. Sure some have a lesser potential to spew contaminants than others. A hand blower like a Giotto's Rocket or better yet, a foot pump like a Sevylor have 1000 times less chance of contaminating your brush and they are much cheaper.
By a Dirty Mirror Box. Your mirror and shutter mechanisms have been oiled & greased as they do have moving parts. Sometimes this lubricant travels to places in the mirror chamber that can be accessed by the brush when trying to clean the sensor. To eliminate this, you need to clean the mirror chamber with a product similar to Visible Dust's Chamber Clean. Cleaning the mirror chamber first before using a brush for the first time is mandatory on the Canon 1D, 1Ds, 1D Mark II and 1Ds Mark II cameras do to the type of paint Canon used in this area on these models.
By Human Skin. DO NOT touch the fibers of the brush with any part of your skin, no matter how recently you washed. There are natural oils on your skin and these show up as smears on your sensor. If you are reading this after the fact (you already touched the fibers of the brush against your skin) you need to wash the brush before using it on the sensor.
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Curt Fargo
http://www.cleaningdigitalcameras.com