If you’ve ever driven anywhere with kids in your car, there’s a good chance you’ve had to deal with milk or formula stains on your upholstery. While spilled milk can leave discolored areas and strong odors on your car seats or floor mats, there’s no need to fret. In this article, we’ll go over the best ways to deal with both fresh and set-in milk stains, as well as that lingering sour milk smell.

This article is based on an interview with our auto detailing expert, Chad Zani. Check out the full interview here.

Method 1
Method 1 of 2:

Cleaning Fresh Milk Stains on Car Upholstery

  1. 1
    Pat the spill dry immediately. The quicker you act, the less likely it is the stain will set in and start to smell nasty. Grab a clean microfiber towel, some paper towels, or a clean rag and gently blot up the spill. Try to soak up as much of the milk as you can.[1]
    • Pat the spilled milk instead of rubbing it, so that you don’t spread it around or push it deeper into the fibers of your car’s upholstery.
    • The same goes for leather upholstery. Aggressive rubbing can force spilled liquids in deeper.[2]
  2. 2
    Sprinkle baking soda on the stain. Baking soda, or sodium bicarbonate, can help soak up additional moisture and neutralize odors. Once you’ve blotted up the spill, pour on enough baking soda to completely cover the area of the spill, then let it sit for at least 15 minutes.[3]
    • Some auto care experts recommend scrubbing the stain with a soft-bristle scrub brush to work the baking soda into the fibers of fabric upholstery.[4]
    • Make sure the area is mostly dry already before you sprinkle on the baking soda. Otherwise, the soda will harden and become difficult to clean up.[5]
    • Baking soda works well for soaking up stains on leather as well as fabric upholstery.[6]
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  3. 3
    Vacuum up the baking soda. If the spill is still damp, use a wet/dry car vac. Vacuum the area thoroughly, until you can’t see any more of the baking soda.[7]
    • If the spill has already started to smell a little sour, leave the baking soda on a bit longer before you vacuum it up. Try to let it sit for at least 60 minutes, or overnight if possible.[8]
    • For leather upholstery, simply buff away the baking soda with a dry cloth.[9]
  4. 4
    Spray any remaining stain on fabric upholstery with a carpet cleaner. If you can still see or smell any spilled milk after you clean up the baking soda, a little carpet or upholstery cleaner may do the trick. Spray the cleaner on the area and pat it dry with a clean microfiber cloth.[10]
    • If you’re not sure whether carpet cleaner is safe to use in your car, you can also get upholstery cleaners specifically designed for cars. Look for these cleaners in your local auto parts store or in the automotive section of a department or hardware store.
    • If you’re worried about lingering odors, follow up by spritzing the stained area with an enzyme-based odor neutralizer. Use a stain or odor remover containing protease, which can break down animal-based stains, such as milk or formula.[11]
  5. 5
    Spot clean deeper stains on leather with a leather cleaner. Leather upholstery can be sensitive to a lot of common household cleaners. If the milk has soaked into your leather car seat, rub the area with a soft, damp rag soaked in a gentle leather cleaner. Blot up any excess moisture with a clean, dry towel when you’re done, then leave the car windows open to let the spot air dry.[12]
    • You can buy cleansers made for leather car upholstery at an auto parts store or in the automotive section of most department or hardware stores.
    • You can also make your own leather cleaner by mixing 1 part water with 1 part vinegar.
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Method 2
Method 2 of 2:

Tackling Old Milk Stains on Car Upholstery

  1. 1
    Vacuum the stained area thoroughly. Before you deal with old, set-in milk stains, clean up any loose dirt and grime so you don’t grind it into your car upholstery. Grab a car vac and go over the area thoroughly until you can’t see any more debris.[13]
  2. 2
    Neutralize light stains with vinegar. White vinegar can break down a variety of stains and odors, including milk.[14] Combine 2 parts warm (but not hot) water and 1 part white vinegar in a spray bottle. Shake the bottle well to combine the water and vinegar, then spray the mixture directly on the stain. Rub the area with a soft, clean microfiber cloth, working in circular motions, until there’s no visible stain remaining.[15]
    • For a little extra cleaning power, add 1 or 2 drops of dish soap to your vinegar solution.
    • If your car has leather upholstery, mix up a 2:1 combination of olive oil and vinegar instead of water and vinegar. Spray the cleaner onto the stain and gently buff the area with a soft cloth.
  3. 3
    Use a chemical stain remover for tougher stains. Because milk contains complex proteins and fats, it can be hard to get it out with regular cleansers.[16] However, there are a variety of stain removers on the market that can remove these types of stains without damaging your car upholstery. Look for a product such as Lightning Fast Stain Remover or Detail King Fiber Pro.[17] Read the instructions carefully to make sure you are using the product safely and correctly.
    • Depending on what kind of cleaner you’re using, you may need to wear gloves to protect your skin from irritation.
    • You can also try using a citrus-based cleaner to break down milk fats.
  4. 4
    Scrub the cleaner into the stain with a scrub brush. If your car upholstery is made of fabric, use a soft-bristle scrub brush. For leather seats, you can use a medium-bristle brush. Spray your stain cleaner onto the milk stain or directly onto the brush, then buff the area with the brush to work the stain cleaner into the fabric.[18]
    • You can also get rotating brushes that attach to a hand drill for quicker stain removal.
  5. 5
    Wipe the area with a dry microfiber towel. Once you’ve scrubbed the stain thoroughly, grab a soft, clean microfiber towel and blot up any excess cleaning solution. Use a light-colored towel so you can see any dirt or discoloration on the towel as you clean.[19]
    • Choose a lint-free cloth so that you don’t leave behind fuzz and debris on your car seat or floor mat.
    • Most car upholstery cleaners don’t have to be rinsed out after you apply them, but check the label on your product to be sure. For instance, you may have to wipe the area with a damp cloth after applying the cleaner.
  6. 6
    Allow the upholstery to air dry. If possible, clean the stain on a dry, sunny day. When you’re done, simply leave the windows open and let any damp areas air out.[20] If that’s not possible, you may need to put a portable dehumidifier in the car and let it run for a while with the windows and doors closed.
    • You can buy a small dehumidifier for under $30, or rent one from a home supply store.
    • You can also speed up the drying process by going over the damp spots with a hair dryer if you don’t have access to a dehumidifier.
  7. 7
    Place an odor absorber in the car to soak up lingering smells. Even with a thorough cleaning, it can be hard to get the smell of spoiled milk out of your car. To tackle tough odors, try placing a commercial car odor absorber next to the spill. You can also try a variety of home remedies, such as:[21]
    • Leaving an open box of baking soda in the car, or sprinkling baking soda on the area where the stain was and leaving it overnight. Vacuum it up the next day.
    • Leaving an open container of coffee beans in the car overnight.
    • Setting a box of kitty litter near the spot where the smell is coming from, or sprinkling litter on the stain.[22]
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About This Article

Chad Zani
Written by:
Auto Detailing Expert
This article was written by Chad Zani and by wikiHow staff writer, Megaera Lorenz, PhD. Chad Zani is the Director of Franchising at Detail Garage, an automotive detailing company with locations around the U.S. and Sweden. Chad is based in the Los Angeles, California area and uses his passion for auto detailing to teach others how to do so as he grows his company nationwide. This article has been viewed 13,692 times.
2 votes - 50%
Co-authors: 5
Updated: May 28, 2022
Views: 13,692
Categories: Drink Stains
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