Inspect the outside furniture for rusted areas. Remove cushions or pillows, if applicable, as well as any detachable parts, allowing you easier access to rusted areas.
Loosen the bigger and visibly peeling rust spots with a thick wire brush, then whisk away the rust particles. Use care when doing this so you do not damage the furniture.
Wipe the furniture with a damp cloth, removing any remaining rust particles loosened by the wire brush. Use a towel to thoroughly dry all areas of the furniture.
Put on rubber gloves and using a sponge apply an oxalic acid cleaner to remove difficult rust spots. This type of cleaner is available at home improvement stores. Carefully follow directions on the container before using.
Scrub affected areas with a hard scrub brush to effectively remove all rust from the metal furniture.
Rinse the furniture with clean water and dry with a towel. If you missed any rust spots, repeat the process.