I received your message yesterday, but for some reason my reply was not delivered. I don't know if it is because the number was a google number. But, anyway.
If you are referring to the face of the plane, then you should use a flat surface, like the glass and sand paper. Maybe start around 220 or 320 and work up to 1,000 to high. The rest of the plane I would clean with a wire brush, I use a Dremel with a brass or stainless brush.