I used a wipe on gun blueing solution on my breast and back. It was easy to do, just time consuming to get right. It has aged very well, in my opinion. My armor has the look of worn and aged "munition" armor. I also used a different solution on one of my helmets and it turned out dreadfull, despite my taking my time. I've since given this helmet to my sargeant to paint, it will be used in conjunction with a different breast and back that will be painted. If you decide to go the blueing method, I recomend the 44/40 brand solution, apply it LIBERALLY. Let it set for a few minutes to a few hours, depending on your desired finish (longer will be darker), then THOROUGHLY wipe down the metal with oil, I recoment Kroil Oil (comes in an orange can). Let it sit some more, as it will rust more and then retreat with oil until the rusting stops. Patience and care are you main strongpoints in this. If you have brass or other fittings you do not wish to cover, use painters tape to tape them off until the blueing has been applied and wiped off at least once with oil.