stupid question how do you get these stainless wiper arms off?

I got a 1963 dart and my original stainless steel wiper blades won't come off. I would just reuse the orginals with new rubber refills but they're all bent up and when I tried the refills on they worked poorly. So I bought some new stainless tricos that look pretty good but I'm having the hardest time trying to remove the old stainless arms. Anybody have any tips? I had a 66 dart back in the 2000's that someone had installed modern black plastic arms on so I know that removing the original arms has to be possible!

Thanks for any tips.

Paul