What is the best way to clean fingerprints or smudges from the front facing part of the hybrid viewfinder on and X100/X100S/X-Pro 1? Microfiber cloth? Lenspen? What about the rear facing side? The same?
I just brush it off first to get the dust particles, then use little warm breath on the glass to loosen any oil or dirt before applying the lens pen or cloth. No cleaning solution is really needed in my experience, though a full 'wet cleaning' like people do for lenses certainly isn't going to hurt anything.