removing a windshield rearview mirror?

To remove the mirror itself use a allen key at the bottom base of the mirror. If you want to remove the metal bracket it is very tricky it takes lots of Patience. You need a heat gun and a vise grip. First attach the vise grip on the metal bracket. Secondly apply heat with the heat gun in a circular motion from the outside of the windshield. Begin twisting the bracket with the vise very lightly. It will loosen up eventually, repeat method.Good luck

to remove the mirror only there is an allen head bolt at the base of the mirror take it out lift off mirror to remove the glue use a strait razor blade

Auto parts store should have a solvent to disolve the adhesive. If not, check with a Ford MEchanic

Better to remove the mirror only and use the armature from your new one, this should be an easy enough modification.