Dartin for Divorce

Black sharpie will turn purple in the sun. Cheap AR manufacturers will use it to touch up anodize rack marks on the black parts. The Caswells pens are the right ones to use, but the paint doesn't flow very well.

Here's a trick: buy some water based acrylic model paints. Mix a drop of dawn detergent into a capful and thin it with water to just thicker than milk. Do a few costs, let dry and then you can use a paper towel or microfiber towel to wipe over it and leave only color behind in the debossed marks.

It's a technique used for "oil washing" plastic models to bring out. Minor details like panel lines.