Originally posted by zosxavius So tomorrow I will be wiping the sensor down and cleaning my horribly filthy focusing screen and hopefully I will get the finger smudges off of it this time.
Just to be sure here, you wouldn't be the first person to think there was a fingerprint on their focusing screen, when they were actually seeing the textured grain on it. It looks something like a fingerprint at smaller apertures. In any case, the focusing screen is very soft and you will probably scratch it up by wiping it down with anything.
As far as cleaning goes, I haven't had to delve into wet cleanings yet. I use a soft artist's brush to loosen any dust, then a blower to (hopefully) remove it, and I repeat the process until it's clean. It can be a bit tedious, but it's very gentle on the filter.