Wiper Arm Spring

[71-SS350]

Since the wiper arm spring on the driver side took it's leave from the arm sometime ago (??) just want to know, is it possible to change the spring or replace it? Hope to remove a spring from a spare passenger arm and use it for a replacement. For the passenger side I would just change the arm as I have a couple spares. Naturally it has to be the drivers side of which I have no spare. Also what's the best way to remove the arm without damaging the paint or windshield?