No one I know can reproduce that bevelled glass for your windshield rear view mirror so I took
mine apart and had the glass re silvered at a Mirror plating company. It cost me about 36 dollars for 3 Mirrors.
They are difficult to take apart but if you are real carefull
you can take a heat gun and heat the back of the Mirror
untill the glue becomes pliable and then jently lift the rubber form the steel with a thin flat screw driver to start the parting and continue to heat the steel periodicly
to maintain the heat on the steel. Continue to strip the rubber off of the steel.Then when it comes off you need to heat the back of the rubber untill the glass comes off of the rubber.Be verry carefull not to over heat the rubber as it will start burning. Before you take apart your own mirror I would suggest that you practice on your friends mirror. Or another mirror that is no good.Clean the rubber
with a paint thinner untill it is looking new. Then polish the stainless back untill it shines again to your liking. Use crazy glue to put it back first the mirror on the rubber and then the rubber on the steel. Be quick about it as the glue sets fast. I have done about 6 already and they came out better than GM made them.
Remember to use gloves and dont forget to lubricate the swivel before you reassemble.
Good luck
PJ