Naval jelly is a product which is commonly used for rust removal. The product is available at most local hardware stores, and it can be ordered online from certain retailers.
What it is
Naval jelly is basically a gel solution that has been infused with phosphoric acid. The gel form makes it functional for removing set-in rust stains, and it retains the properties of phosphoric acid.
How it works
When placed on a rust stain, the phosphoric acid interacts with the iron oxide in rust. The interaction transforms it into iron phosphate, a substance that can be easily removed.
How to use
The Loctite products Website for naval jelly states that you can simply brush the gel on, watch the rust dissolve and rinse it off.
Using naval jelly to remove rust can extend the life of mechanical parts. Removing rust and making regular repairs can make machines last years longer.
As with all chemical products, be sure to wear protective clothing such as gloves and goggles when using naval jelly to decrease the risk of injury from exposure.