Give new life to dirty, rusty outdoor metal or wrought iron patio furniture with spray paint. learn how to clean and paint outdoor metal furniture and restore metal outdoor furniture by removing rust and chipped paint with a wire wheel. Then remove mildew with a bleach and water solution. Rinse thoroughly to remove all chemicals. Then prime with several light coats. Once that is dry, paint outdoor metal furniture in the spray paint color of your choice for a new, fresh look.