yup, just another washed mirror thread!
but just for newbies I thought i'd share my experience
I have had my scope for ages now! (when did i buy it? 2 years ago or is it one (time flies)) and the primary had a considerable amount of dust, hair and paint flakes on it. "PAINT FLAKES???? " i hear you ask. the paint has started flaking off the top of the scope and is settling on the primary mirror and surrounds (not large amounts mind you).
anyhow I decided it was well and truely time as the only cleaning the mirror has had is a bit of blowing stuff off. I bought some demiineralised water from supercheap auto ($1.50 per ltr or there abouts) and couldnt wait to get home.
At the bottom end of the OTA there are about 6 screws holding the bottom in - removed them. then with a straight edge screwdriver i slowly edged it out of the bottom of the tube and rested it on a teatowl in the dining room (so as to not scratch the table). next I fought our cat off as he wanted to help.
Cat removed i unscrewed and removed the mirror clamps, removed the mirror by holding the non-coated edge area and carefully placed it in the scrubbed sink which was about 1/3 full of warm soapy water... I let is sit for a little while...
With a piece of sterile cotton wool held under the water resting lightly on top of the mirror surface i made slow circular motions moving from the middle of the mirror out to the edge removing all the built up gunk. i did not at any time push down on the mirror. Next i fought the cat off again (3 times), he like playing in water.

Drained the sink and rinsed the soap off with warm water splashed on from the tap. rinsed with the demineralised water and set to air drying. I soaked up some larger drops of water with the tip of a tissue (just touching the water not the mirror).
...put everything back together (the reverse of the taking apart above) and wallah!!!
now all i have to do is recollimate and test. I also took the opportunity to remove the metal plate from the bottom (easy work).