[Arkady]

Don't use any fluid on the CCD or bypass screen - EVER! if it won't come off with a blower and a gentle wipe with a proper cleaning pad, leave it and get the camera serviced by the manufacturer.
Canon UK and Nikon UK both do Professional Services for Pro Phots (that just means if you bought a Pro-spec camera you are eligable) - I take mine in whenever I come back from somewhere dusty and it's a half-day turnaround if you ask nicely.

These cameras are pretty well sealed though unless you take the lenses off. We had one of the COP guys (just camera operators for surveillance jobs) drop his D1 into the bottom of a muddy trench then tread on it while he was scrambling around. When he tried to hand it back covered in mud, the storeman told him in no uncertain terms to clean it off. Being a bright lad, he took it to the vehicle wash-down point and jet-washed the camera!
It was fine - no water ingress at all. When Nikon heard about it (as they do) they asked if they could use the story in an Ad campaign - we said no coz it made us look like a right bunch of nobs!
People from Nikon still ask if it's a true story, whenever they find out I'm an army phot. Sad to say it is...