Canon EOS 1D Mark III Instruction Manual page 136

3 Manual Sensor Cleaning
While cleaning the sensor, never do any of the following. If the
power is cut off, the shutter will close and the shutter curtains and
imaging sensor might get damaged.
• Set the power switch to <2>.
• Remove/insert the battery.
The surface of the image sensor is extremely delicate. Clean the sensor
with care.
Use a plain blower without any brush attached. A brush can scratch the
sensor.
Do not insert the blower tip inside the camera beyond the lens mount. If
the power is turned off, the shutter will close and the shutter curtains or
reflex mirror might get damaged.
Never use canned air or gas to clean the sensor. The blowing force can
damage the sensor or the spray gas can freeze on the sensor.
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