Painting Galvanized Metal
Although I already mentioned wrought iron, there are other metal surfaces around your house that could stand a coat of paint at times. Metal eave strips, valley tin, and even roof vents can all be painted. The challenge is preparing the surface properly.
Most of these metals are galvanized; and paint, typically, doesn’t stick to them. The secret is a common item you probably have in your kitchen pantry. Take a rag and dip it in household white vinegar, swab the metal surface with the soaked rag, and allow it to dry. A chemical reaction occurs between the metal and acidic vinegar to create a surface that any spray paint will adhere to.
Roof vents are probably the best thing to spray paint, because you can paint it a color to match your shingles and help make the vent blend into the color of the roof. It really looks a lot better than a dull, rusty metal vent.