I am currently crafting a pair of post apocalyptic bracers. I first made a cardboard model and then cut out the shape of an small oil barrel with an angle grinder. I wanted to have the nice letters and this ringe shape in it. I sanded them to let them rust. I put them into a mixture of water, salt, acetic acid and bleach. It began to rust after minutes. Don’t leave them completely dived in. Just water them from time to time. I will leave them in the rain for some days now.