Thanks Mike....gotta do something nice for the diligent ants, slaving away at home while the grasshoppers play at OSH
Let's fix a run.
Grab a razor blade and a piece of 400 or 600 grit paper. Hold the blade at a slant as shown and drag it across the paper a dozen times. You just put a microscopic curl on the edge:
Now bend the razor blade like so, curled edge on the convex side:
Here's our run.....ugly, ain't it?
Drag the edge of the blade across the high spot in the run, holding it nearly perpendicular to the surface and using only light pressure. Don't try to cut or dig or anything like that...just sort of drag it. It will scrape very light feathers of material off the run with each pass. The bend in the razor isn't strictly necessary in this example, but if the run was on a flat surface it would prevent you from dragging the corners of the blade and making a scratch. In this case it just shows you which side has the curl.