Rust, also called corrosion, forms on unprotected metal surfaces when oxygen and water combine to cause oxidation. Oxidation creates iron oxide, which is the scientific name for rust. Factors such as salt in water and heat accelerate the rust-forming process. In addition, natural occurring substances carried in water can form rust-colored stains in certain situations. There are a number of ways to remove rust and rust stains, depending on the situation.
The best method for removing rust from metal depends on the item affected by corrosion. Sand blasting, or bead blasting, is a common method to remove rust from auto parts. Because sand blasting techniques often remove a portion of non-rusted metal, blasting with glass beads is more effective for sensitive parts. Sandpaper and steel wool are good alternatives for removing corrosion by hand, although these methods often leave rust in porous surfaces. Porous metal rust removal is often accomplished with a rubber abrasive sanding block. Using chemical rust removal products containing phosphoric or hydrochloric acid are favorable for quickly removing corrosion. Oxalic acid is also a rust removal chemical. The best technique for removing rust without damaging the remaining non-rusted metal is by an electrolytic process, which electrically eliminates corrosion with the aid of an alkali solution. This process is also safer than other chemical methods.
Fine grades of steel wool are commonly used to remove rust from chrome surfaces. Any grade of steel wool leaves minute scratches in the chrome that can be polished out later. Steel wool soap pads, often used as a household cleaning item, are a good way to both remove chrome rust and prevent scratches, since the water acts as a lubricant by washing away tiny steel wool particles.
Mineral deposits contained in water can build up on porcelain surfaces around faucets, drains and toilets, creating a rust stain. Vinegar works as an effective porcelain rust remover due to its mild acidity. For tough-to-remove rust stains, cleaning products containing gluconic or hydrochloric acid are effective; test the product beforehand to ensure it does not scratch the surface of your porcelain.
Removing rust stains from clothing can be accomplished by using citric acid, contained in lemon juice, or acetic acid found in white vinegar. Over the counter products designed to remove rust stains in fabric are effective because they contain oxalic or hydrofluoric acid. Avoid placing rust-stained clothes in a dryer prior to treating, as heat can cause the rust to set into the fabric. Chlorine bleach may permanently set the stain as well.
Hard water contains a high concentration of minerals that often cause rust stains on porcelain and can make cleaning a task difficult. Systems, called water softeners, such as ion exchange units and electronic or magnetic water conditioners, are effective means to reduce mineral deposits in water.