I just took a paint pen, pushed the tip into a small plastic cup to create a small pool of paint, then dabbed it on with a touch up paint applicator from Griotts Garage (small plastic sticks with a little sponge upon the tip). Have a paper towel handy to wipe off paint that gets on the raised letters. Before applying new paint, I used a “Nik-sand” tool (a bundle of fiberglas fibers) to flake off remaining loose paint and rough up the paint that didn’t come off.