I stumbled across a good idea. I use "link & pin" coupling for my cars. The area around the coupler box is usually plastic or brass or white metal. I needed some more pins so I took some 8 penny finishing nails, cut them to 1", rattle painted them red ozide primer. Then discovered an added feature. When the need to remove the "pin", I use a magnet which lifts the metal 8 penny nail and doesn't disturb the brass, plastic or white metal. Still have to use tweezers to install them, working on that!!