[ithacaartist]

OK Eric... Bluing is an oxide layer on the surface of the steel. Its thickness in in the range of a few molecules. Abrasion will remove it. A grinding wheel would be one extreme of abrading away the finish layer, but it will happen eventually if the pistol is rubbed on anything often enough. If you can remember rubbing a penny on the carpet when you were a kid to shine it up, it's basically the same thing. The bluing on the grip straps is handled over and over, and simply wears away where it's repeatedly contacted. Dirty hands and their perspiration will take their toll. Inserting and removing a pistol from a holster, however soft, will do the same thing wherever the holster is rubbed by the gun on its way in and out. Voila! Holster wear! It happens mostly on the high spots and corners because they stick out the farthest and are the first areas rubbed. If we extend this thought to the elevated, "upset" steel pushed up and out from under a die hammered into the surface, it is obvious that its peaks are susceptible to bluing loss simply because they stick up a little bit compared to the surrounding, undisturbed surface. I hope this is a satisfactory and coherent explanation...