[astro_nutt]

Hi all,
Last time I had to clean the primary on my 10" dob was due to spilt liquid.
Firstly I mark the spot where the mirror sits in it's cell with a drop of liquid paper on the cell and a permanent marker on the side of the mirror.
I used canned air and gently blow away any loose dust.
I clean the laundry trough with clean water to remove any dirt or soap and dry throughly.
Remove any soap holders, hoses, cloths, even the curtain!
Place a clean towel on a table next to the trough.
Fill the trough with about 4 inches of luke-warm water.
Place a drop of dishwashing detergent in a large drinking glass and fill with water, stir and pour 2 tablespoons into the trough.
Gently immurse the mirror into the trough and move it side-to-side for about 1minute, turn it 90 degrees and move it side-to-side for about 1 minute.
Empty the trough and remove the plug, turn on the tap, and rinse the mirror using moderate pressure, (as you would wash your hands) with luke-warm water, starting from the centre outwards.
After rinsing with tap water, do the final rinse with distilled water by running the distilled water across the mirrors surface while hold the mirror on a slight angle. Starting from the top of the mirror so as the distilled water will flow off the mirrors surface.
Dry off any droplets with the corner of a tissue.
After I did this, I noticed a swirl pattern on the mirror's surface. I later found out that this was a result of oxidization between the overcoating and the aluminium coating and has not affected the image quality at all!! ( I later learned that this wasn't caused by washing it!)
As for dust on the mirror, I just use a puffer, only if I really have to!
Cheers!