The constant light exposure on the mirror does modify the optical characteristics, and a wet wipe once in a while seems to help. Every time I wet-clean my sensor, I use the "dirty" sensorswab to wipe of the mirror and the exposed surface of the focus screen.
"Every time I wet-clean my sensor, I use the "dirty" sensorswab to wipe of the mirror "
Be careful. Not certain about the current models, but in the old days, SLR mirrors had pretty thin coatings on them and it was very easy to scratch them. And - mirrors are carefully aligned. Touching them risks knocking them out of alignment.
My buddies at NPS always told me to basically keep my hand (and anything else) off the mirror unless absolutely necessary. Manual bulb blower only!
Whether that is still so these days - I really don't know, but why chance it? Does your mirror really get that dirty that you need to clean it every time you clean the sensor?
Dust can be puffed off with a bulb.
Tread gently my friend!
Oops - didn't notice that you said you ocassionally clean the mirror. Nontheless - I would vote for just leaving it be.
Thanks for the warning. I can't see how the mirror can be more scratch sensitive than the low-pass filter in front of the sensor. On the frequency --- I don't wet clean my filter more than once every 6 months, sometimes even once a year. Have not had a problem so far, but I do tend to tread lightly down there.