Followup on wet-cleaning sensor

There are really two surfaces inside the camera, the one that drops down when you choose clean sensor and another up above it toward the top of the camera. Anyone try to clean that one also?

Methinks you don't understand the parts inside the camera's mirror box. When you invoke the sensor cleaning mode, the mirror goes up - covering the focussing screen - and the shutter opens thus revealing the sensor. What two surfaces are you referring to?

You don't want to touch the mirror surface (it's an extremely delicate front-surfaced mirror), the focusing screen (which is above the mirror), or the shutter blades.

I think OP is referring to the focus screen. Yes you can clean it but be careful it's plastic not glass. My 5D makes removal pretty easy not sure about the other models. If your focus screen is dirty you'll see it when you look through the view finder but the specs wont be on your photos themselves.

Oh, ok, I understand that. Thanks.