Spilled milk can soak deep into your car upholstery and leave a lasting stench. It doesn't matter if it's old or new stains. There are several ways you can get your car smelling fresh again and prevent your car from smelling like spoiled milk again when you spill milk again.
Steps
Method 1 of 3: Remove all spills

Step 1. Pat all spilled milk dry
Immediately after spilling milk, blot up any excess milk that is still wet and still visible. This will help get the smell of spoiled milk out of your car and make it easier to clean the area later.
Use paper towels, a white washcloth or sponge and press it against the fabric or upholstery where you spilled milk. Continue to dab the area until you have absorbed all the moisture

Step 2. Remove and wash the floor mats and seat covers
Remove all substances and objects that you have spilled milk on and that you can get loose.
- Floor mats without plastic and rubber can be washed in the washing machine. Spray stain remover on the mats and wash them in the washing machine with warm water.
- Spray all other materials with a garden hose or wash them in a tub of soap and water. Air dry the mats indoors or let them dry outside in the sun.

Step 3. Use a wet vacuum
Use a deep-cleaning wet vacuum or steam cleaner to remove any putrid milk odors that have soaked deep into your car's upholstery. Many steam cleaners use products with special cleaning ingredients to remove odors from food residues. This can help you get rid of the smell of spoiled milk.

Step 4. Hire a professional
If your car still smells like rotten milk after trying home remedies, the smell may have soaked into your upholstery so much that simple methods can't get to it. In such a case, ask a professional who knows a lot about cleaning car upholstery or a car salesman to have the car professionally cleaned to get rid of the smell of spoiled milk.
Method 2 of 3: Neutralize and remove the odor

Step 1. Use ground coffee to remove stubborn odors
Ground coffee helps absorb the smell of spoiled milk and leaves a coffee smell in your car that helps disguise unpleasant odors.
Fill plastic containers with ground coffee and slide them under your car seats. Leave them there for about two weeks

Step 2. Harness the power of baking soda
Sprinkle a layer of baking soda on the affected area to absorb moisture and absorb the smell of spoiled milk. Baking soda filters the air and removes bad odors.
Let the spill area dry completely before sprinkling baking soda on it. Leave the baking soda for three to four days, then vacuum it out of the upholstery

Step 3. Spray white vinegar on the spot
Vinegar works very well at removing bad odors, so try using vinegar if your car smells like rotten milk. It helps to break down the enzymes of the milk that have been absorbed into the car upholstery and reduces the bad smell. Best of all, vinegar is safe to use and contains no hazardous chemicals.
- Mix one part white vinegar with four parts water in a spray bottle. Spray the vinegar mixture on the affected area until it is completely soaked. Leave the mixture on for four to five hours, then pat the area dry with a white washcloth.
- Leave your car windows open to allow air to flow through them.

Step 4. Try an enzyme spray
Buy an enzyme cleaner from a hardware store near you and spray it on the spilled areas. The spray will break down the odor residue and leave a fresh scent.
- Leave the enzyme spray on for one to two days and then pat the areas dry.
- Do not use such a spray on leather and suede.

Step 5. Try it with carpet cleaner
A carpet cleaner contains strong chemicals that thoroughly clean fabrics and upholstery. Just make sure to dry the upholstery completely after cleaning with carpet cleaner.
Read the directions on the package to see how long to leave on and then vacuum up with a vacuum cleaner

Step 6. Air out your car
One of the reasons that a car starts to smell like spoiled milk is because the moisture remains in the car and mold starts to grow. After spills and while cleaning, open the windows and park your car in the sun so the upholstery can dry and fresh air can flow in.
Method 3 of 3: Preventing your car from smelling like milk again

Step 1. Wipe up spills immediately
The longer milk or other liquid stays in your car, the harder it is to remove the stain and odor. The faster you absorb the liquid, the greater the chance that there will be no unpleasant odor.

Step 2. Let fresh air flow in
After you spill milk, it's always a good idea to leave the car windows open for a few hours. This allows all the milk liquid that has evaporated into the air of your car to be blown away and fresh air can flow into your car.

Step 3. Keep the inside of your car clean
Food and liquids provide a good breeding ground for bacteria, so that they multiply and unpleasant odors can arise. Vacuuming your car regularly and beating your floor mats is an excellent method to prevent bad odors.