Yep; it's similar to how barbers rub their razors on leather-- called "stropping," IIRC. It apparently smooths out any microscopic dings in the blades' edge. It

Yep; it's similar to how barbers rub their razors on leather-- called "stropping," IIRC. It apparently smooths out any microscopic dings in the blades' edge. It also helps to realign the blades in the case of those multi-blade cartridges.