Cleaning Aluminized Telescope Mirrors           

Big mirrors seem to have a fatal attraction to kitchen sinks. 
Mirrors are much happier on their back on the lawn, just watch out for the reflection of the sun.
Forget about that lens cleaning kit with the little bottles of stuff.  That won't do this job.
Other things that won't work, vinegar, silver polish, and  no, never use cleanser or similar.

We will presume this mirror has been in a flood or a tornado and is covered with grit glued down with plant resins.
So water spray alone will take some of the large grit away.
Note, yes this mirror is not coated but it was available at the moment.

The significant items in this picture are two pans of almost hot water, dish washing detergent, paper towels and semiconductor grade methyl alcohol warmed in the sun.  And no slip shoes and be very careful.
Alternatives:
rubbing alcohol
Kimwipes
cotton balls
some types of toilet paper
blotter paper

Put a bit of dish washing liquid in one pan and soak the paper towel until soft.
Wipe the mirror lightly, don't press down.
Move to the rinse pan.  That was easy, now the hard part.
Carefully remove the mirror from the pan and pour alcohol over it to get rid of the water.
Tip the mirror up to get rid of excess alcohol.   A bit of pre planning helps.
Before the drops of alcohol can dry drag a dry towel sheet across the mirror to spread out the alcohol.
Don't press down while dragging the towel.  
Then put the mirror in a safe place and lay a towel on it and take a break.

The mirror's coating becomes much harder after several years making the cleaning process easier.

 

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