Mirror Rinse

I realize optical cleaning has been done to death, but I could not find a thread that mentioned exactly what I am looking for. I have built my first 12.5" f/4.89 open truss dob. It is an ultralight system and does not have a mirror box so the mirror is extremely vulnerable to the elements/dust. Before I could build a mirror cover and a light shroud the mirror collected a bit of dust from the collimation process/ star testing / a couple of public star watches. I would like the easiest safest mirror rinse. Ideally something that did not have to be wiped down yet still would not leave a residue. I have a can of compressed air but would like something a bit more cleansing, plus I have heard horror stories about the canned air. I imagine with a open truss design I might run into this problem more often than most. I also realize most recommend not to clean optics unless absolutely necessary, but I sure do miss that freshly coated new mirror shine!
Is there such an animal out there or something I can create??
Thanks,

Todd

Hello:
I also built a light weight 12.5" dob. I too was worried about the mirror being so exposed close to the ground, near dirt, pebbles, people's shoes kicking up dirt and pebbles, etc. I found that a large vinyl flower pot (the largest they had at the local WalMart) would fit around the mirror. I cut a large hole in the bottom for ventilation, and so that the bottom of the flower pot was trapped between the back of the mirror cell and the tailgate structure. When the telescope is stored, I put a lid on the flower pot. This seems to keep the mirror pretty clean.
As far as cleaning an already dusty mirror, this is a bit trickier. Canned air can spit out drops of liquid air, which is very cold. The thermal shock can shatter a good sized lens, but I haven't heard of this happening to a 12.5" mirror. I have considered using my airbrush (without the paint, of course!) to blow the dust away. At the observatories here, they use CO2 snow to blow dust off of the mirrors. Most amateurs would probably be shocked to see how dirty the BIG mirrors get before they get a water wash. So, I'd recommend making a mirror cover for your mirror to protect it, clean it off in the sink as usual, then leave it covered at all times it's not catching star light.

Cheers
Mike Connelley

Interestingly, a study was done with photometer and a random selection of mirrors. If was found that a dusty mirror lost 11% of the light! 8O So much for the old wives tale that a dusty mirror did not effect viewing!