Wiper Arm Removal

I'm preparing to start the body work on my hood and cowl, but can't figure out how to remove my wiper arms.

A guy I used to work with gave me a tool that is supposed to do it, but it didn't work. He suggested using a pair of channel locks to gently work them off the stem.

Is there any kind of clip or retainer on those arms? Anyone know of any tricks?

Thanks.