Wrong. If you foul up the mirror your camera loses the ability to autofocus. This is why the mirror is semi transparent. Only some of the light is delivered to the viewfinder, the rest goes to the AF system. This is also why there's sometimes a mirror behind the mirror. This is also why I don't recommend touching the mirror in the slightest. If you bend something it's a trip to the repair house.
As for cleaning I used a q-tip once. Worked well. Wouldn't do if I had a choice. I didn't at the time. I was overseas in the middle of nowhere. It left a smudge and I had to reclean when I got home. Pretty much most of the sensor cleaning solutions out there are suitable.