How to Remove Rust with Phosphoric Acid

Rust is a crusty corrosive condition that occurs on metal when it is exposed to air and moisture. Small areas of rust present an unattractive appearance on the surface of the metal object. If left untreated, the rust will spread until it actually forms a hole in the metal. One effective rust-removal solution is to use phosphoric acid in gel form to dissolve the corrosion.

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Clean rust from metal with phosphoric acid.

Step 1

Move the rusty object to a well-ventilated outdoor location.

Step 2

Put on long sleeves, pants, protective gloves and safety glasses before opening the can of phosphoric acid jelly.

Step 3

Apply the jelly to the rusty object using a paintbrush until the entire object is coated with the jelly. Cover even the non-rusted parts because the acid will provide a slight protective finish to those areas. Allow the phosphoric acid jelly to sit for the amount of time recommended by the manufacturer.

Step 4

Scrub the rusted areas of the metal object with a piece of steel wool to remove the rust. The rust will easily come off as you scrub. If the rust does not come off easily, allow the jelly to sit for five additional minutes.

Step 5

Rinse off the entire metal object with a garden hose to remove most of the phosphoric acid jelly.

Step 6

Sprinkle baking soda onto the surface of the metal object until it is coated.

Step 7

Scrub the surface of the object with a scrub brush and rinse with water from a garden hose. The baking soda neutralizes the acid and stops it from continuing to act on the metal. Allow the metal object to air dry.