It's been discussed before and like Gasman says it still leaves the pitting. With that said, it does take the rust out and pretty much will clean the rust to the bottom of the pitting. So it would not only save sandpaper, wear and tear on your muscles but would also do a nice job of cleaning if you wanted to leave some of the pitting.

I've got an old charger that I've had laying around waiting to stumble upon a razor that is really rusted to play with and see how it does.

The one thing I don't know how they would be affected would be trying to do it with the razor on the scales ie the brass pins, washers etc. I can't see it harming scales but---------------------