I clean keyboards with water - put them in the sink and run water over them and perhaps use an old tooth brush to scrub a little.  Perhaps this would work on a gentler scale with the camera.  It is important to let it dry thoroughly, I tend to use the sun as we are having a drought but hair dryers also work (but not too hot!).  I learned this trick from an IT person years ago.  Alcohol sounds a bit drastic but many people seem to turn to it.
                 Larry
                
 February 2007