In my opinion, there's too much emphasis placed on the
danger of mirror cleaning and i've read many people all over the world taking all of these over the top precautions, and leaving years of built up crud on the mirror for fear of washing it off.
Again, it's only my opinion, but in my experience, it's really not hard to do and i've had no negative effect on my mirror or the quality of my view.
I've cleaned my mirror 2 or 3 times now (I've had the scope just over 12 months), as it can get quite dirty from dust, dog hair, dried up dew etc, and simply the light scatter from all these particles are bound to give a worse view.
Sure, I was a bit nervous the first time (because of all the tales of possible doom!) but if you treat it carefully, like you'd expect anyone to do when they're holding a mirror, then it shouldn't be such a scary thing to do.
Just take precautions -
1) Ensure your work area, sink etc, is prepared. Room to move, place to lay the mirror down, etc.
2) Take it out of the back of the OTA, just grab the mirror cell by the edges and ease it out backwards.
3) Leave the mirror attached to the mirror cell until you get it up next to the sink.
4) Undo the clamps, and just make sure you have a firm grip of the edge of the mirror when lifting it out of the cell. Then wrap your hands underneath as well.
5) In a sink with lukewarm slightly soapy water, let it rest for a bit, then using a cottom ball wipe lightly in strokes across the mirror, turn the cotton ball once and then throw away.
6) Angle the mirror and rinse with water from the tap for several minutes
7) Use distilled water, followed by blower brush or the corner or a paper towel to soak up the last drops that don't run off.
8) Let it dry, put it back in the mirror cell the same way you took it out, don't do the mirror clamps up tight - only very lightly (just) touching the mirror.
9) Back in the OTA the same way you took it out.
Don't forget to collimate, and then you're done!
It's not that hard to do, just be careful..
I'm sure people don't leave their eyepieces all cruddied up with dew stains, eyelash stains for fear of cleaning them, so why that attitude with the mirror? yeh if you drop it it's not going to be a good thing, but if you drop your $500+ nagler it's also not a good thing. And the mass produced GSO mirrors that most of us newt owners around here own, would cost less to replace than a nagler anyway
Anyway, just my opinion