ATM Mystery Mirror

["Nathan L. Allen" <nathan@ebs330.eb.uah.edu>]

        I have obtained a mirror from work that has been laying
around for years. It was originally used in CO2 laser research
of some kind. The mirror finish was originally Gold but has
deteriorated significantly. It is 8" in diameter , and the glass
(or what ever it is made of) is very clear and free of defects.
My question is how do I determine the focal length. There was 
another mirror with it that indicated it was built in 1973 and
had a R.C. of 32 feet, imagine THAT telescope :>.
Also , How would I remove the remnants of the gold surfacing ? .
And I would like to determine what it was made of , there is a
barcode of some sort on the back.

                                Any help would be appreciated

                                Nathan Allen