BBadger wrote:Another thing to remember is that some lenses will suck in air when you zoom or focus which can pull dust into the camera. A camera with a sensor vibration system may help remove some of that dust if it gets into your camera. If it gets in the lens itself, I have no idea how you'll get it out. I would also bring a clear plastic bag to do all your lens swapping in as a sort of "cleanroom."
Nikon lenses (and I'm sure Canon are no different) can be taken apart and cleaned. Its a bit of a pucker moment when you crack open that $1200 lens for the first time because you can see micro dust particles inside of it, but it isn't too bad after the first time.
Usually, any internal dust or particulate matter are in between the first 2 elements. Not sure how much deeper into a lens I would try to go though. If you can see gunk in deeper, best bet would be a good camera shop.
ON, and it is usually a good idea to drop off your camera after the event and have it professionally cleaned, especially the mainstream consumer level models. Prosumer/pro level gear is usually sealed up pretty well. My D300 has gone 3 years and I have not had it cleaned. I probably should, but have not had any issues.