After having parked my car in a newly constructed airport parking garage, I came back to find something had dripped through a crack in the ceiling of the structure and left considerably thick film on my car. On a glass window surface, I tested soap and water, mineral spirits, two types of latex paint remover (i.e. goof off), and household chlorine bleach. None were effective. But plain white 5% vinegar dissolved the film if I let it soak or scrubbed on it with a cloth.

car window showing places where vinegar was effective at cleaning off a film

My question: is an acid of the strength of vinegar a risk to automotive "paint" (the top layer is probably "clear coat").

  • $\begingroup$ I'd try using a paper towel wet with vinegar and just stick it to the surface of the car. Then use a spay gun to give it a good squirt. I think the worse thing you can with such a coating is rub. I'd be worried about scratching the clear coat and/or paint. Take the paper towel off and rinse with water while you rub gently with your fingers. $\endgroup$
    – MaxW
    Jul 2, 2019 at 3:06
  • $\begingroup$ Vinegar is not a strong enough or corrosive enough substance to damage paint and you can minimise the risk by using a cloth or sponge wet with vinegar on the glass and not spraying the whole car or leaving it in the surface for an extended period. Also, it is a good agent for removing what is almost certainly a limescale-like layer (basically a carbonate that will react with acids). $\endgroup$
    – matt_black
    Aug 15, 2020 at 12:40

2 Answers 2


That is a valid question, because acid rain has been known to damage paints, particularly high-gloss, i.e. clear coat. Best would be to test the effect of vinegar on a hidden area, and double-check under bright light from different angles. Your idea to test on glass is good, because it shows how long a soak is needed.

  • If it appears unaffected, rinse afterwards with a weak solution of baking soda or ammonia, and then rinse again with plain water to remove any remaining acid.

  • If damage is slight, can car wax effect a good repair?

  • If vinegar does damage in the test spot, you might look at various car polishes or even cutting compounds, and then wax (or reapply a gloss coat, which may mean refinishing a large section of bodywork to get it to match).


Vinegar Test: No Visible Change After Two Hours

As advised above, I decided to test vinegar on an inconspicuous spot.

First I created a pattern of exposed paint using masking tape. The shape was just something random that I thought I could most easily recognize, even if just a slight difference in the car's finish:

masking tape on part of car's exterior paint

Then I placed vinegar-soaked cloth on the test area of the car:

Vinegar soaked cloth on auto paint

After two hours (which was longer than I expected the cleaning of the other parts of the car to take), I removed the cloth, rinsed the area, and finally just washed the are normally:

test area of car with soapy water

And finally took the car into various lighting conditions. There was no detectable difference in the finish that I could see:

clean and dry with no visible damage


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