Sensor cleaning of a Canon EOS 350 DSLR camera back to projects
I own an EOS 350 DSLR, and of course there has been some dust accumulated on the sensor. Dust particles can easily be removed with some compressed air, like with these small ball-pumps. Better not use pressurized air from a compressor unit. This air will most probably be 'oily' and will contaminate your sensor even more. Furthermore, a too strong airflow may damage the internals of the camera! Harder to remove particles can be removed by (wet) cleaning with a swab.
When you activate the 'sensor cleaning' function, the missor will flip up and the shutter will open, then you will see a blueish shiny surface. In front of the sensitive area is an infrared filter, which is a piece of filter glass with probably a coating on it. This is the piece where dust is accumulated. It is possible to clean this glass but be careful not to scratch it, although it is strong, the coating may be more fragile.
Some time ago I've been cleaning the glass, and suddenly I discovered as if the cotton swab (see below) had scratched the glass, bit of a panic there. A replacement glass would have cost around 250 Euros. I decided to try it again, as I thought that it was ruined anyway, but the scratch was just a trace of oily substance! simply rubbing the glass with some isopropanol did the trick and the sensor was superclean again!
How to do it
Make a swab from lens tissue by rolling a small piece (3*3 cm) to a roll.
Bend the roll as seen halfway the photo and use some tape to fix it to a stick (cotton swab or something). Make sure that there is some room left between the stick and the end of the swab.
Carefully swab the sensor of the DSLR camera with it to remove dust and other stuff. If this is not enough then try putting some IPA (Isopropanol, probably alcohol will do also) on the swab and clean the sensor with this.
The real sensor is actually behind an infrared filter, so you will not touch the actual sensor but only this infrared filter. This infrared filter is made of glass with probably a sort of coating. This looks very sensitive and delicate but it is not really. Be careful though, since a scratch on this layer can be seen on your photographs when the diafragm is closed more (F8 and higher), but do not worry too much when cleaning. If the surface gets stained when you try to clean the surface with IPA, then most probably there was some grease on the swab (probably some skin-fat/oil). Make a new swab, and do it again. Only move in one direction with the swab, so do not make circles or rub the surface, only sweep across the surface. Press with absolute minimal force. The complete process will take time and nerves, so do take your time, and be calm. Be gentle and patient! (reserve half an hour or so for this job)
I will not take responsibility for damage, just trying to help. If you have problams with controlling very small movements (shake-movement larger than 1mm) then this operation is not recommended.