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How to Use CLR Rust Removal on Cars

by John Walker

Rust occurs when untreated iron oxidizes in the presence of water or humidity. The metal on cars is painted with polyurethane-based paints to protect the body and frame from rust. Time and exposure to the elements chips away at the paint until the bare metal is exposed and rust begins to develop. Using a powerful angle-grinder on the surface creates metal shavings and can cut through the metal. You can use CLR Calcium, Lime & Rust Remover to make removing rust from your car's body easier and less damaging.

Spray the rusted area thoroughly with CLR Calcium, Lime & Rust Remover. Allow that to stand for five to 15 minutes.

Use steel wool to sand the surface by hand, removing the bulk of the rust.

Spray the area a second time, allowing it to stand for five to 15 minutes.

Use 100-grit sandpaper to remove the remainder of the rust. Repeat the process with 150-grit sandpaper to leave the surface smooth.

Thoroughly clean the area with soapy water, using a rag to scrub the area. Rinse thoroughly and allow to dry before applying any form of sealant to the surface of the metal.


  • CLR loosens up surface stains caused by rust but does not remove rust. Hand-sanding actually removes the rust after CLR loosens the substance.
  • Using the sandpaper by hand limits damage to the underlying metal.


  • CLR is a corrosive chemical. Spraying onto paint could damage the polyurethane top coating. Use great care when applying the chemical to the surface of a vehicle.

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