Photoclubalpha

I appreciate it is not actually the sensor but the glass in front of it.
I have had the camera about a year and three months ago experienced problems with what I thought was dust but it truned out to be oil. I had failed to clean the 'dust' and ended up at having it professionally cleaned.
After three months I have the problem back again.
It was suggested to me that factory over enthusiastic lubrication in the shutter area could be the cause.
Is this likely? If so what do I do to prevent it recurring after I have paid another pro-cleaning cost.
It is most frustrating.

It is a common problem with all makes. You should be able to clean oil spots off using a pec-pad type cleaning kit (solvent solution with a soft lint free wipe on a paddle).

You need to be gentle, as the oil from Canon professional shutters often contains bits of metal or composite from the shutter mechanism - presumably the much less stressed Sony A350 shutter is unlikely to start wearing away its own parts, but the possibility for the oil drop to contain a hard particle remains, so never press a pad heavily on the sensor.

David

This happened to me too. It was worth paying a pro to take it off for me ($80). The penatly for failure here is too high for me to screw it up.