Witness Marks

What’s the preferred product for making witness marks on mounting screws and whatnot?

http://www.sharpie.com/enUS/Product/Sharpie_Oil-Based_Paint_Marker_Medium.html.

Thank you much.

That is what I use as well. Another tip is that if you ever want to remove the marks denatured alcohol removes them entirely even after a long time. Stick with the oil based though if you have a choice. The alternative is a water based which will run when it gets wet.

I also use the green to paint my front sights, make them a little easier to pick up.