I'm working on some decorative items made of copper. I'd like to have them achieve the brown color of an old copper penny (or the old copper pipes in my home). I've read you can do this with some chemicals, but due to size/shape I'd like to do this some other way. I'm also concerned that any sort of chemical that I would apply would not give an even appearance. I could bake these in an oven - will that help? What temperature? Would adding moisture help? Or does this just take months/years? I would wash them with detergent first to remove any oils, and scrub with an abrasive pad to expose an even, 'fresh' copper surface.