Rust is the product of a chemical reaction between iron and oxygen. When an oxygen molecule comes into contact with an iron molecule, it forms iron oxide, or rust, and it's more than just an eyesore. If left untreated, rust can ultimately ruin whatever object it affects. As the corrosion process continues, more metal is exposed to rust, which eventually weakens the metal to the point where it either crumbles or is no longer useful. Whenever you discover rust on a valuable possession, it's important to remove it as quickly as possible. WD-40 helps remove rust by breaking down the bonds between metal and rust.
Spray the rusted surface with WD-40, enough to thoroughly soak the area. Allow it sit for up to 10 minutes.
Clean the rusted item with a wire brush. With the rust loosened, the brush should clean away most of the corrosion. Brush the surface until you're satisfied you removed most of the rust.
Spray another application of WD-40 on the surface and let it sit for five to 10 minutes.
Use sandpaper to remove any remaining rust. You may use 120- to 160-grit sandpaper for moderate rust and 80-grit or coarser paper for heavy, severe rust. Be sure to remove all of the rust you possibly can. Any rust you leave will contribute to the growth of more rust.
Reapply WD-40 as needed for stubborn areas of rust, allowing it to soak before you continue sanding or brushing.
Rub the area with steel wool to buff the metal and remove the smallest remnants of rust. After you've removed all of the rust, coat the surface with an application of WD-40. This will provide a protective barrier against future corrosion.