A quick simple wipe of the sensor did the trick for me. Check it out in the full post.
I got tired of the accumulated dirt on my sensor and decided to do something about it. I was going to buy a cleaning kit, and still might, but before I did that I wanted to try it myself with a few items I had lying around the house.
I grabbed some cotton swabs and a bottle of window cleaner. "Woah there Nelly!" I'm sure some of you are saying, "That's a delicate instrument there and you don't want to mess it up". Well, I hear ya, but here is my reasoning behind why I thought this was OK to do.
First off, the sensor is behind several panes of glass (filters) so any contact is not done on the actual sensor itself. The IR filter is glass so why not use glass cleaner on it?
Second off, I'm sure the sensor unit is sealed and no liquid can get
Armed with this knowledge I decided to try the cotton swab alone to gently wipe the IR filter. As I suspected it didn't remove any spots. The camera's built-in sensor cleaner (the clunk-clunk) hadn't shaken any dirt loose so why would a quick gentle wipe with a Q-Tip do any better.
So I decided to just barely (feathered the spray) on the cotton swab and used my fingers to get the light mist to soak into the swab.
I then used a gentle sideways sweeping motion to clean the IR filter. It worked great. The only visible item was a fresh cotton fiber from the cotton swab. Another gentle swipe removed this fiber and the sensor was clean enough for use.
Even though there was no visible dirt on the sensor I wanted to see if any thing would become visible with an extreme contrast adjustment. Sure enough there was a smudge visible. But it's not enough to worry about. I most likely will introduce more lint on the now spotless IR filter. So I'm leaving it.
So why this experiment? To see if in dire straits the IR filter could be cleaned with cotton swab and glass cleaner when a kit wasn't handy. Do I recommend doing this under normal circumstances? Probably not. Buy a kit with lint free tip and cleaning solution that is approved for your camera. If you're stuck on a deserted island with a dirty sensor and a crate of Q-Tips and Windex washes ashore, go ahead and clean the sensor.
Until next time, go shoot something with your clean sensor!
Edit 29 Apr 09: Edited wording on sealed sensor and liquid getting in the sensor.
Edit 18 July 09: Windex Original MSDS