I was just given a new, very plain Zippo. I'm bored, so I'm thinking maybe I should try and print on the case. Now, this is my question.... How best should I proceed? I'd be using Liquid Light, and I'd be printing on the metal. Should I sub it, print on it, then cover it in a clear acrylic? Or should I just rough the metal a bit, and print on it without a sub, and then coat the final product? I've never worked on metal before.