Well, the reason Ford went to the glue-on mirror instead of the solid-mount was for safety. The Feds said that people were getting hurt or killed by hitting their head on that during an accident, so they started requiring breakaway mirrors.
...therefore, just hit it really hard with your head....it SHOULD come off.
Seriously though....use a candle. Heat up the button for a couple of minutes then insert a screwdriver between the windshield and the button. Tap downward with a hammer on the screwdriver. The button will fall right off and won't leave a scratch. (Cover your dashpad first with a wet towel....when it drops, it'll be hot.)