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Cleaning rust off asphalt driveway

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25K views 29 replies 24 participants last post by  KitCarson3  
Get some Rust Mort from Napa and put it in a garden sprayer, it'll turn the rust black so it blends in.
I was going to suggest phosphoric acid too, which is the active ingredient in Rust Mort. Also sold at Lowe's in Jasco Prep and Primer and Home Depot in Klean Strip Prep & Etch. Another popular brand is Skyco's Ospho, which I've heard of, but never actually seen in person.

As stated, it'll turn the rust to a black(ish) color (iron oxide changed by phosphoric acid to iron phosphate). Should do a good job on fairly thin stains that it can fully penetrate/convert. If there are "larger" particles still embedded in the asphalt, those may re-rust after additional rain and/or wear from traffic. Obviously test on a small area before going hog wild on the whole parking lot.