I had read that the coins might be difficult to read in bright sunlight, so I proactively bought a bottle of India ink and a brush, and used a technique I have used to paint spaceship models. I just spread out the coins face up on newspaper and painted the whole face black, edge to edge. Then I wiped off the face with a paper towel. Most of the ink is rubbed off, but the ink that remains fills in the recesses and edges and really bumps up the detail contrast. The captain coins already had that look to them. It took about an hour to do all four ships, and it made a big difference in the ability to read them at a glance in the direct sunlight.