Just got finished removing most of corrosion with vinegar water,the the stubborn spots with straight vinegar. Used a scotchbrite pad a little also.
Letting everything dry overnight then a light touch with fine emory paper and painting (I think).
The metal didn't react by bubbling when hit with vinegar so am sure it's not magnesium, not sure it's aluminum either seems like a zinc pot metal
or something. I don't believe I've ever seen a white thick corrosion on any thing like that except battery posts,so am wondering about some zinc mix.
More to come.....