Last Updated on March 19, 2025 by Nate Schnell
Picture this: it’s a sunny Saturday afternoon, and your car needs some TLC. But there’s one catch—you’re completely out of car wash soap. Don’t worry; you probably have everything you need right in your own kitchen to make an effective homemade car wash solution.
I’ve washed a lot of cars over the years, and trust me, sometimes the simplest solutions are the most effective. Let’s walk through how you can quickly make homemade car wash soap and some safe, practical alternatives.
Why Make Homemade Car Wash Soap?
Before we dive into the recipes, you might wonder why you’d even consider a homemade soap in the first place. Aside from being budget-friendly, homemade soap is convenient and often gentler than commercial cleaners, which can contain harsh chemicals. DIY soap reduces plastic waste and is easier on your wallet without sacrificing cleaning power—provided you mix and use it correctly.
Now, let’s look at how to mix and use homemade car wash soap properly.
How to Make Homemade Car Wash Soap
Here’s a straightforward recipe that works well without causing any harm to your car’s paint. You’ll need basic household items:
Ingredients:
- 1 cup mild liquid dish soap (like Dawn, preferably gentle and unscented)
- 1 tablespoon baking soda (optional, for additional cleaning power)
- 1 bucket of warm water
First, fill a clean bucket with warm water—about 3 gallons is sufficient. Next, add about a cup of mild liquid dish soap to the water. If your car is exceptionally dirty or has stubborn stains, you can add ¼ cup of baking soda as a mild abrasive, but avoid going overboard. Baking soda is safe on paint, but too much can be overly abrasive, especially if your car has a delicate clear coat.
Mix the solution gently, making sure it creates enough suds without becoming overly foamy.
Once you’ve mixed your soap solution, set it aside and prepare your car for washing.
Preparing Your Car for Washing
Before you use your homemade car wash soap, it’s important to pre-rinse your car with clean water. A thorough rinse helps loosen dirt and grime, significantly reducing the risk of scratches. Ideally, use warm water for rinsing, but cold water is fine if it’s all you have available.
Once your car is rinsed thoroughly, dip a soft microfiber wash mitt or towel into your homemade soap solution and gently wash the car. Always work from top to bottom, so you don’t drag dirt upward onto previously cleaned sections.
Why Dish Soap Works Well—but With a Catch
Dish soap is fantastic for cutting through grease and dirt, making it a great emergency substitute for regular car wash soap. However, there’s a catch: dish soap will strip away any existing car wax or sealant from your vehicle’s surface.
So, if your car was recently waxed, I’d recommend avoiding dish soap and choosing a gentler alternative like baby shampoo. Alternatively, if you do end up using dish soap, plan to reapply car wax afterward to protect your paint and maintain that shiny, protective finish.
Alternatives to Dish Soap: Baby Shampoo and Hand Soap
If you’d prefer something milder, baby shampoo or mild hand soap are good alternatives. Baby shampoo is gentle enough that it won’t harm your car’s clear coat or strip wax. Simply use it the same way as dish soap—mix about half a cup of baby shampoo with a bucket of warm water. It won’t foam up quite as much, but it cleans gently and effectively.
Hand soap can also work, but since it tends to have moisturizers and fragrances added, it may leave residues behind, making it less ideal. If you choose hand soap, make sure to rinse thoroughly afterward to avoid streaking.
Washing Your Car With Homemade Soap—Tips for Best Results
Once you’ve made your soap solution, wash your car from top to bottom, rinsing the wash mitt frequently in clean water to avoid dragging dirt across the paint. Use a gentle touch, as excessive force can lead to swirl marks and scratches.
Work in small sections, rinsing frequently to ensure that soap residue doesn’t dry on your car’s paint. Rinse your car thoroughly afterward, using a garden hose or pressure washer set on low. This helps ensure no soap residue remains, which could dull the finish if left behind.
Finally, dry your car with a clean microfiber towel or drying cloth. This step is important to avoid water spots and streaks, leaving your car shiny and spotless.
Additional Tips to Enhance Your Homemade Car Wash
If you find that your homemade solution isn’t quite cutting through tougher grime or stains, you can add a little vinegar—about a quarter cup—to the mix. Vinegar is safe on automotive surfaces and helps dissolve minerals and bird droppings. Just don’t use vinegar if your car was recently waxed, as it can remove wax as well.
For those stubborn windshield stains, a paste of baking soda and warm water applied directly to the glass can be very effective. Let it sit for a few minutes before gently rinsing off.
Can Laundry Detergent Be a Good Alternative?
Laundry detergent can be a viable option in a pinch, especially mild liquid detergents without added fabric softeners or bleach. Use only a small amount—a tablespoon or two mixed with a bucket of water is usually enough. Laundry detergent cleans well but, like dish soap, it can remove wax and sealants, so use caution and be prepared to wax your car afterward.
Drying and Waxing After Using Homemade Soap
Once your vehicle is clean and rinsed, dry it thoroughly to prevent water spots and streaks. Use a clean microfiber towel or a soft drying chamois. Avoid air drying or direct sunlight drying, as it can leave water spots on the finish.
If you’ve used a homemade soap that removes wax, like dish soap or laundry detergent, apply a fresh layer of wax after drying. Waxing regularly protects your car’s clear coat, helps repel dirt, and keeps your paint looking shiny and new.
FAQs About Homemade Car Wash Soap
A common question I get is, “Can homemade car wash soap actually harm my car’s paint?” The simple answer is no—as long as you stick to gentle household products like mild dish soap, baby shampoo, or mild laundry detergent and avoid harsh chemicals.
Another frequently asked question: “How often should I wash my car with homemade soap?” Typically, washing your car every two weeks is sufficient, although it depends on your driving conditions and how dirty your vehicle gets. Since homemade car wash soap can strip wax, you might consider alternating between commercial car soap and your DIY mix.
Finally, many ask, “Is homemade soap effective on wheels and tires?” The answer is yes, though for heavily soiled wheels you may still want a dedicated wheel cleaner. Still, homemade solutions work great for regular maintenance washes.
Final Thoughts
Making your own car wash soap can be quick, easy, and effective, especially when you’re out of your usual supplies. Plus, it’s budget-friendly, environmentally conscious, and can be adapted based on what you already have in your home. As long as you’re aware of the limitations—particularly regarding wax removal—you’ll find homemade car wash soap an excellent solution to keep your car looking its best without a trip to the store.
