[robski]

I find I have to clean my sensor every few months. One of the worst things you can do is blow into the chamber with your mouth. Tiny droplets of moisture stick to the sensor. I normally use the vacuum cleaner with pipe only to suck out dust as the first line of attack. Make sure the vacuum cleaner body is in another room stirring up the dust from it's exhaust. I also wear those medical rubber gloves, a cotton tee shirt and a cap on the head to prevent bits coming from me adding to the problem.