Capping scratchers are used to get to low spots of the honey frame. Some folks will use these instead of a capping knife. It does work, but you will do more damage to the combs and make your filtering a little more difficult. Perhaps its best use is to pull capped drone brood from a frame to help identify the mite load that your bees may be carrying and get a better picture of when you may need to think about treating for mites.
Color may vary.