Rust accumulates on door hinges when moisture is allowed to build up on the surface of the metal. The moisture mixes with oxygen and forms rust. In addition to its unsightly appearance, rust can corrode and weaken the structure of metal, causing holes to appear and increasing the possibility of the hinge breaking or snapping when the door opens. To avoid these potentially dangerous effects, door hinges should be checked periodically, and any rust found should be removed immediately.
Remove the door hinge. Use a screwdriver to remove the hinge plates from the door.
Scrub the door hinge with steel wool. Remove as much rust as possible, but expect rust to remain near the edges and around the screw holes.
Place the hinge in a container. Fill the container with basic cola, such as Pepsi, Coca-Cola or a generic substitute. Carbonated beverages contain phosphoric and carbonic acids, which remove rust via etching.
Check the hinge for rust every three hours. Depending on the extent of the rust, it may take more than a day to dissolve. Remove the door hinge once all signs of rust are gone.
Clean the hinge with liquid dish detergent and warm water to remove any stickiness. Dry the hinge completely with a towel, and then reinstall the door.
Add a tablespoon of citric acid to the cola to speed up rust removal.
Remove the hinge from the cola as soon as all signs of rust are gone. Leaving hinges in cola for extended amounts of time causes the metal to turn more brittle.