Cheapest way is to go to a hobby shop, buy some paint, humbrol or tamiya in enamel.. cost you a few bucks
get some nice pointy toothpicks, open the cap and just dip the tip of the toothpick into the paint thats in the cap, that way you only get small amounts each time, and just touch up the spots. once the area is filled, let it dry and then re do it and build up a nice thick layer... then you can clear coat it and sand it and polish. But if you dont care, just leave the black to dry and it will be visibly fine and tough...
get some nice pointy toothpicks, open the cap and just dip the tip of the toothpick into the paint thats in the cap, that way you only get small amounts each time, and just touch up the spots. once the area is filled, let it dry and then re do it and build up a nice thick layer... then you can clear coat it and sand it and polish. But if you dont care, just leave the black to dry and it will be visibly fine and tough...