What Eats Rust?
Rust is a common problem when working with metals. When water with electrolytes comes into contact with iron, it creates hydroxide acids. This is why rusting is common around salt water, since there are more electrolytes present to promote oxidation. Once the metal is exposed to water and oxygen, the iron begins to corrode. This will not stop until the exposed area is treated by removing all the corrosion and then resealed.
Soaking or applying vinegar to rusted metal is a great way to loosen and remove the rust. Vinegar is an acidic substance, thus will help break the rust apart and allow it to be scrubbed off with a tough material such as steel wool or a brush. This should be done outside in warm weather, since vinegar will produce fumes and the heat will make the rust dissolve quicker. After removing all of the rust, immediately wash the metal with water and soap, since the vinegar acid will continue to eat away at metals. Reseal or paint the metal to prevent further rusting.
Salt and Lime
The acid in limes, and other citrus fruits, will help break apart rust so that it can be removed from metal objects. Wipe the lime or lemon on the affected metal, then sprinkle some salt on it. Allow this to sit for a few hours, and then scrub it with either the lime peel or a brush. Rinse and scrub any remaining residue off and then allow to completely dry before treating the metal.
Baking soda is a great cleaner that will help remove rust. Mix the baking soda with water to create a paste that you can apply to rusted metals. Let this paste dry. It will help loosen the rust and reduce corrosion. Scrub off the paste once it has dried, rinse the area off and then reseal the metal.
Soda, or any other carbonated drink, is a great way to remove rust. Carbonated drinks have carbon dioxide mixed with water, which makes carbonic acid. This acid can reduce or reverse corrosion caused by iron oxidation. Also, many carbonated beverages contain phosphoric acid, which dissolves iron oxide and does not eat away metallic iron. Let the rusted piece soak in a carbonated drink for a while, or apply it to the rusted surface and let it sit for a few hours. Then rinse it off and scrub the piece clean.