I bet you didn't think you'd see that subject on a gun forum! 
I just picked up an M&P Pro 9mm last week and I wanted to color in the engraved parts. I couldn't decide on a color, and I didn't want to mess the gun up while experimenting, so I decided to test it out on the magazines.
Yellow, white, and silver were the colors I tried. I also did a green, but it wasn't showing up very well on the black metal. I really like all three of these, but I think the yellow might be a little over the top. I kind of want it look like maybe it belongs there instead of something I bedazzled my gun with.
At first, I was leaning towards white so that it would match my M&P 22, but it looks like the white etching is starting to rub off of the 22 already. I also think the white seems a little too bright.
Now I'm kind of digging the silver (although it could have used another coat). It makes the emblems stand out, but it's also kind of subdued.
I think I'm also going to try a dull shade of yellow and green and see how those turn out.. I wanted to try green because of the color of the fiber optic sight, but as I said, the green I tried didn't show up much. Maybe if I lay down a base coat of yellow and put green on top of that, it will come out right.
My girlfriend's nail polish collection is going to be put to the test! Any other colors you guys recommend trying?
As a side note for anyone thinking of painting their guns with nail polish, I found that whatever the non-acetone nail polish remover wouldn't take of.. Hoppes #9 solvent did. I left a white haze on my magazine that I was getting concerned wouldn't come out after wiping it down with the polish remover, but the Hoppes #9 took it off.

I just picked up an M&P Pro 9mm last week and I wanted to color in the engraved parts. I couldn't decide on a color, and I didn't want to mess the gun up while experimenting, so I decided to test it out on the magazines.
Yellow, white, and silver were the colors I tried. I also did a green, but it wasn't showing up very well on the black metal. I really like all three of these, but I think the yellow might be a little over the top. I kind of want it look like maybe it belongs there instead of something I bedazzled my gun with.
At first, I was leaning towards white so that it would match my M&P 22, but it looks like the white etching is starting to rub off of the 22 already. I also think the white seems a little too bright.
Now I'm kind of digging the silver (although it could have used another coat). It makes the emblems stand out, but it's also kind of subdued.
I think I'm also going to try a dull shade of yellow and green and see how those turn out.. I wanted to try green because of the color of the fiber optic sight, but as I said, the green I tried didn't show up much. Maybe if I lay down a base coat of yellow and put green on top of that, it will come out right.
My girlfriend's nail polish collection is going to be put to the test! Any other colors you guys recommend trying?
As a side note for anyone thinking of painting their guns with nail polish, I found that whatever the non-acetone nail polish remover wouldn't take of.. Hoppes #9 solvent did. I left a white haze on my magazine that I was getting concerned wouldn't come out after wiping it down with the polish remover, but the Hoppes #9 took it off.