# how to clean front surface mirrors



## jkaiser3000 (Mar 1, 2006)

I just got a couple of front surface mirrors, and wanted to know how to best keep them clean. I suspect using alcohol or some other liquids may destroy the aluminized coating, and using some cotton fabric may scratch the surface, so....
:help:

thanks


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## LumenHound (Mar 1, 2006)

Step by step easy to follow instructions on cleaning first surface mirrors and coated optics. Most people wouldn't think to clean the mirror under water.

Here's the link.


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## bootleg2go (Mar 1, 2006)

Being an amature astronomer and cleaning many a eyepieces, optics and mirrors. Here is the best way.

Use a camera lens cleaning brush with a "blow bulb" tand lightly go over the surface to remove most of the dirt/dust.

The get some surgical cotton (like for wound dressings), avoid normal cotton balls as they often have debris and other nasty stuff in them.

Also get some acetone from the hardware store, make sure that too does not have any other impurities in it as well.

Dab a little acetone onto a piece of the surgical cotton (don't saturate it), then, with the mirror on it's edge (not laying flat), very gently wipe from top to bottom in strokes (don't go in circles or scrub). Do this only once if possible and not more than twice. If there are any streaks left (with experience they can be avoided), get some of the disposible, wet camera lens wipes and very lightly go over just the streaks.

You should not do this often, I try to limit this kind of cleaning to once or less per year. The more it is cleaned, the sooner you will get a scratch it the surface. After this just use the camera brush until the next year.

Also store the mirror/lens in a way so as to limit exposure to dust and keep it covered when not in use.

Acetone won't hurt aluminized coatings or any other optical coating on "real glass" mirrors or lenses. Don't use acetone on plastic or non-glass lenses as it will melt and ruin them.

bootleg2go


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## LumenHound (Mar 1, 2006)

Acetone _will_ work better than denatured alcohol, ethanol, or methanol when it comes to greasy stains like fingerprint smudges but you really need to use 100% pure acetone and you will find it's very difficult to obtain comercially. Do not expect to walk into the local drug store and find it next to the nail polish remover. You may find 90% pure acetone but it's that other 10% that you need to be worried about.

Acetone also has a tendency to remove paint from metal surfaces so you would have to be extreamly careful cleaning a first surface mirror with a painted metal mount. You don't want to end up smearing paint onto the mirror.

Never, and I mean NEVER use acetone on binocular or camera lenses. Use only alcohol. Camera and binocular lenses are always surrounded by either painted metal or plastic and the acetone will damage the plastic and dissove the paint off the metal.

If your going to use a solvent, start with a small amount of alcohol, ethanol, or methanol. 

I've found it's best to start with the most benign fluid first and then progress to stronger fluids if need be.


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## IsaacHayes (Mar 1, 2006)

Hmm I have a small monoclular that was submerged in water and has junk on the lenses and mirrors. I might try to clean it...


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