Good find, Brendon. If you have a chisel where the back is lightly pitted or not flat, using lapping compound and a flat steel plate will get it looking pristine again. You could also do it on a stone, but the plate stays flat and the compound will cut faster. There are different grits of compound, and they will bring a pristine surface as they break down and polish. Most chisels or plane irons aren't truly flat to begin with, it is good to lap them.