02 Escape rear wiper arm

This past winter the pivot on the rear wiper arm got so much corrosion in it that the spring won't pull the blade tight against the window any more. To further complicate it, the corrosion worked its way into the nub that the arm slides over. I can get the retaining clip to slide up out of the way very easily. I've been spraying it with various penetrating products a couple times a day for the last two week. I've got a huge pair of channel locks that I can grab at the back edge of the arm without catching the nub. I don't put pressure on the arm that would squeeze it onto the nub, just enough that I can slightly rock it while pulling hard. It is not coming off. Any suggestions that won't break the window? I know if I have to replace the arm I could cut across or grind it down just short of the nub to get it off, but I'd like to get it off without doing that to see if I can just clean out the pivot and reuse it. Next time I'll be sure to put anti-seize on the nub whichever way it goes, new or old:banghead: .