I'm sure we all have had the same problem. When I receive an order of blades, I take the time to place them top to bottom by either eyesite (not very good at that any longer) or use the thumb process. Then I place them in the holders with the top of all the blades up so when I insert a new blade, I will know right away which end goes up. Painting would be a great idea, but I would be worried the paint would make the blades to large to fit into the holder...I could be wrong on this.
Larry