Zinc Blackening Kit. Instructions: Make sure the Gloves and Mouth Mask and Eye Protectors provided are worn before starting the process. Gently pour the Zinc Black Solution into the kit tub and immerse your items into the liquid which will start to go black. Leave for approximately 10 minutes, remove carefully when completely black and rinse thouroughly in water. Dry with the soft cloth provided. The black zinc surface should be treated with oil, varnish or lacquer to protect it, or to provide a more glossy finish. This product can be used many times before having to be replaced.