Please read the entire description before attempting this process!
Dust, hairs and pollen can easily get "sucked" into the lens as the camera initialises and the barrel extends. They manifest themselves as out of focus dark areas on the image and they do not change size or position as you zoom the camera lens.
In most instances any "sensor" specks of dirt actually occur from the dust settling on infra red filter which is before the CCD itself. To clean the IR filter and the CCD the camera back and inside plates have to be removed before you can gain access. This video shows you how to perform this operation, clean the IR and CCD and then re-assemble the camera.
Using a dust blower will generally remove the dust specs, however if the camera has been used in dust enviroments or in high air pollution such as cities then there is also a possibility of a "film" of contamination also on the surface of the IR filter. Using my technique of the cotton bud removes the film thus restoring any lack of contrast due to this film. If you IR filter comes out of the holder on re-installation put the IR filter into the small recess in the lens housing, then the small rubber boot with the widest part uppermost on the IR filter and then gently place the CCD block back on top of the boot and proceed to tighten it down as per video.
I make the statement that although this is a simple task, you undertake this at your own risk and I can accept no responsibility if you "brick" your camera by damaging the LCD ribbon cables, connector latches, the IR filter or the CCD itself.
Work carefully and arrange the case and other screws so that you know where to replace them.
As a precautionary measure against the unlikely event of electrostatic discharge (ESD) causing damage to the electronics of the camera whilst you are working on it it is advisable to wear a suitable wrist strap device available from most electronic spares stores.