I have recently bought 5 straight razors, in good condition, but they have minor black rust marks. I have used from 600 grit up to 1500 grit sandpaper and silverware polish to clean up the blade. In the process I have noticed that the sand paper has made minor scratches making sections of the blades look "cloudy". What can I do (by hand) to get the blade to a beautiful shine? Do I just need to go to a higher grit of sandpaper or is this going to be permanent.

Thanks