Rear view mirror mounting

The heat of the southern summer has done-in the adhesive on the windshield mount of the rear view mirror.

I've purchased an adhesive kit, but must first remove the mirror mounting button from the rear of the adjustable arm.

It appears to be held in place with a strong clip, but I can't seem to dislodge it. Are there any tricks to separting the mount from the arm without breaking it or gouging my fingers with a screwdriver?

Also, has anyone got any tips for removing the old adhesive from the mounting pad on the glass?

You are sooo lucky.
Now you can mount the mirror high and get a much better view out the back window. Some of us have rotated the mirror to improve the view, but we loose the map lights. Razor blade off the old adhesive. I do not know about the brake away clip, but the adhesive bonds in 3-4 min.
Roy