Nickel- and zinc-plated items can be quite bright and silvery when first plated. These metals are often admired for their brilliance and are polished to achieve a bright and shiny look. However, there is a simple premade chemical solution you can use to antique or tarnish nickel, effectively dulling its shine and giving it an antique appearance.
Clean the nickel- or zinc-plated item to remove dust and dirt from the surface. Use a clean cotton cloth and water to remove accumulated grime from the copper piece and a cotton swab for the details. Gently dab the surface to remove excess moisture.
Apply copper cleaner/nickel to a cloth and gently rub the cloth over the nickel or zinc plated item item, taking care to not be too aggressive. Using another clean and dry cloth, rub off excess polish and buff the copper to make sure you have an even finish.
Apply a darkening solution with a soft towel. A darkening solution instantly tarnishes nickel- or zinc-plated surfaces. Once you achieve the color that you want, rinse the item in water and towel it dry.
Test the darkening solution in an area that is not readily visible to make sure you don't damage the piece.
Use any chemicals in a well-ventilated area.