OMy, that is a nice machine and you should not be trepedacious about the finish. The crinkle finish is very stable. I would only be careful around the Singer emblem on the arm.
If you look in the tutorials and stickies on the top of the page you should find some ways to clean it. I would suggest EvapORust for the plated parts. They probably have a thin layer or rust or oil.
Good luck. It will make a great treadle if you decide to go that way.