Typically you can use a rusting agent, like muriatic acid, to pre-rust or speed the rusting process of the metal. The metal here is reclaimed and left unfinished. Some folks like to put a clear sealer to protect and keep the finish from rusting.

Use a muriatic acid spray on the pans while they are laying flat outside. This way the pans will get frost/rain/environmental moisture on them. You will be amazed at how quickly they rust up! Make sure to wear a respirator and gloves while spraying the acid, as they smell is awful! The longer the pans lay flat to accept moisture, the darker the patina will be.

Please check out our Instagram (@somrak_concept) to see some photos of the end result of our rusting method we used for a house we just finished!