We always sold wiper blades and wiper arms at our gas stations until we went self serve in the early 70's. Getting wiper arms off without scratching the chrome was always a trick so most everyone had a tool to remove the wiper arms. I have no idea what happened to all of the ones we had and had almost forgotten they existed. I saw one on eBay and it arrived last Saturday.

http://www.ebay.com/itm/Vintage-60s-nos-MAC-windshield-wiper-arm-removal-auto-car-tool-accessory-part-/311385896767?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2047675.l2557&nma=true&si=ctQ0RybtBs7hWlbcaCXAMF0MeAc%253D&orig_cvip=true&rt=nc

Its new and still works like they did 50 or 60 years ago.