Considered the most durable material for outdoor furniture, metal can last a lifetime if you take care of it properly. Most metal outdoor furniture is finished with paint, varnish, or powder coating to prevent rust. And, while aluminum doesn’t rust–hence its recommended use in areas near salt water–it can oxidize (which causes pitting and dulls the finish). Metal furniture is best cleaned with a cloth or sponge using water and mild, non-detergent soap and wiped dry. Abrasive scrubbers or cleaners should not be used as they can scratch the finish, potentially exposing the metal to rust-inducing moisture. For ingrained dirt, use window cleaner or a non-abrasive multi-purpose cleaner. Keep reading the tutorial in the source.