If the mirror has been out of the mount before it's eaiser to remove. I prefer to stand outside the car(drivers side, since I'm a rightie)) grabbing mostly the stalk towards the bottom and pulling sideways(with a locked elbow) gently forcing the passenger side of the spring down and out of the mount in a very controlled way. Shoving it toward the windshield might be risky for some
The hanger trick looks neat but I'd probably scratch something with it. If you place the mirror in a freezer for a 1/2 hour, it makes installing into the mount eaiser, using the cold to compress the spring a bit.