In order to maintain tattoos on-set, be aware. Like any makeup you do—but even more like a prosthetic makeup—things can happen. An actor sleeps hard over lunch, an actor rubs his arms on a table while eating, the scene requires actors to wrestle or sweat or run, etc. Always have backup tattoos with you, and alcohol in case you have to remove and apply a new one on-set. Do not remove with oils in the middle of the day because your next one won’t stick. If it is a minor repair, have a premixed color or colors to match the image and to fill in the areas that have rubbed away. Sometimes just throw your hands up in the air, assess the shot, and say: “Hope we don’t see that!” Things happen—just be resourceful and prepared.