Inspect the furniture for rust. Remove any visible rust with steel wool or a wire brush. Stubborn rust can be removed with a chemical rust remover, applied with a rag and then rinsed off.
Sand the entire surface lightly with sandpaper. Sand more forcefully on areas with chipping paint to make the entire surface smooth.
Wipe away any paint chips or dust created by sanding with a tack cloth. Clean the surface with a household detergent or mineral spirits and allow it to dry.
Apply a primer designed for outdoor metal furniture. Use a spray paint to avoid leaving brush strokes and ensure that you get into the nooks and crannies often present in metal furniture. Allow the primer to dry per the instructions on the product.
Apply two coats of exterior spray paint to the furniture. To get even coverage, move the paint can from side to side as you go and keep the paint in constant motion to avoid drip marks.