This camera came in with a very dirty sensor.  It was left outside overnight in damp weather with out a lens mounted on the camera.  The camera worked but the sensor was covered in dried water spots and dirt, thus affecting picture quality.  I felt the best approach to this cleaning was to disassemble the camera and remove the sensor assembly.  I did just that and was able to remove all of the dust and water spots.  There was no signs of further damage to any of the circuitry or internal components so I reassembled and it tested fine.  Note: if I had tried to clean this sensor without disassembly I may have scratched the low pass filter due to the amount of dirt and dust residue.