A friend was using that sprayfoam in a can and got it on his hands, that stuff would not come off. He tried hand cleaner, paint thinner, gasoline, diesel, goof off, just about everything he could think of but that stuff would not come off.
It wore off his skin in a few weeks, his hands looked very strange and dirty until that stuff wore off.
I don't think you will find anything to get it off the metal, Hal has a good solution, sand it off or buff it off and do the whole section so it is even.
There are just some jobs that you can't do or don't want to do no matter if it could make you the hero, the downside is that it can make you look very bad if something gets screwed up. As nice as those doors are, I would not take a chance. Maybe recommend a metal polisher guy can polish it out.