Don't touch the colors.

Look at blued trapguns...Perazzis especially. The bluing wear on the bottom of the actions is from contact with the hands and from draping the gun over the forearm. Those blued actions are more durable, and more easily restored than a colored action. Nothing will reliably protect the colors from the abrasion of constant handling.

The best way to extend the life of the colors is to form the habit of breaking the gun open and resting the muzzle on a pad while you wait your turn. Practice shooting an entire round without ever touching the receiver and then incorporate those moves into your routine.