have been looking into it.
no i havent done a wet clean. i mean "clean image sensor" in the setup menu.
as i'm in japan i might get the official lens cleaning kit from nikon to take back to new zealand, as there is only one authorised servicer in new zealand (not in my city) i will need to learn to do it myself.
they can do it the first time though.
its really noticeable at small f stops and close distances (ie with the lens mentioned).