Allen,
I do something similar to what smalljaw does. I take a small dowel rod and sharpen it till the point goes into the hole. Then I heat the blade on the under side, hold the blade on a 45 degree angle or steeper and dust the blade with powder paint until the blade gets covered. Once one side is covered, I let it cool and then flip it over and do the other side with the same procedure, if you want both sides painted.
Couple other things to try and I've used this for kill spots, is take some electric tape or flat black tape and adhere it to the blade, then trim the edges off. You will have to sand the blade a little to get a rough surface, then wipe off and finally stick the tape on.
You can buy colored self adhesive flat black vinyl tape in 8-1/2 x 11 sheets, which you can cut , stick on and trim. I've seen this tape available on line, or you can get it from a graphics sign shop that does lettering and vinyl graphics for boats and trucks.
Some final ideas:
Black Gaffers tape
Matte black pin stripe tape
Black duct tape
Black masking tape