A "magic eraser" is actually a fine abrasive. Think extremely fine sandpaper. I'm guessing it won't scratch very hard surfaces, like glass. But the paint will likely have it's shine or matte finish altered. That may or may not be very noticeable, but will likely depend on where the light is coming from. I'd only try it as a very last resort, and then perhaps feather it out with a very light touch away from the marks.