I have successfully cleaned several mirrors of used scopes I've bought over the years by following a simple procedure. Before I say how I would like to hear from others to see what they have done. It's not as hard as everyone makes it out to be.
The method came from the manual of first Newtonian I bought and I didn't know any better and I believed it to be gospel and it made sense.
I believe not cleaning will cause the coating to deteriorate quicker over time because of natural interaction of the coatings with contaminates that will fall on the mirror and eat away at the coating. So in my opinion a heavily used mirror should be cleaned at least every year and a half or at least every 2 years assuming buildup of dust. Also the dust holds the moisture more easily so the mirrors fog up easier on an all nigher. Opinions.
The method came from the manual of first Newtonian I bought and I didn't know any better and I believed it to be gospel and it made sense.
I believe not cleaning will cause the coating to deteriorate quicker over time because of natural interaction of the coatings with contaminates that will fall on the mirror and eat away at the coating. So in my opinion a heavily used mirror should be cleaned at least every year and a half or at least every 2 years assuming buildup of dust. Also the dust holds the moisture more easily so the mirrors fog up easier on an all nigher. Opinions.