Wash car with Dreft, green soap or all-purpose cleaner?

Washing your car with Dreft, green soap, all-purpose cleaner, Dasty or another detergent?

A question or comment that we often face is: Is it okay to wash your car with Dreft or any kind of dish soap? Whether it's Dreft, Dasty, green soap, an all-purpose cleaner, or whatever doesn't matter. We'll just put it under the “non-car shampoo” category for a moment. So, can and should you wash your car with something other than a car shampoo?

 pH Value detergent.

While we ourselves at Custom Car Care are not chemists, we do have some understanding of chemicals and ingredients in the products that we use on our cars. Hence, we took a look at just what ingredients are in the better-known detergents such as Dreft and Dasty.

When you look at the MSDS or Material Safety Data Sheet where certain (hazardous) ingredients are contained and the details of the composition of the product, we can already confirm some things immediately. The detergents are (never) pH neutral, they are always alkaline with mainly a pH value of 9-12.

This is not necessarily a bad thing, there are plenty of car shampoos that are alkaline with a pH of 9-12. But it does mean that if you have applied protection to your car such as wax, sealant or spray coating then you are going to remove this protection (completely). Possibly this doesn't matter to you since you may not be applying any protection. However, the same goes for dressings such as tire black, trim restorers, bumper black and so on. These will significantly reduce their durability.

Convertible roofs also have problems with this. This is because these are treated with a water-repellent coating that does not withstand high or low pH well.

We wrote another blog post about pH neutral car shampoo and alkaline shampoo, you can always read it if you want to learn more about this.

Solvents in detergent

Besides the pH value in dishwashing detergent, the chemicals that are in it are also important, of course. What we see a lot of in their ingredients is citrus. Citrus is a pretty strong solvent based on natural solvents that is also used in the detailing world. So does this then mean that it is good to use as soap? No, detailers in fact “never” use citrus as a hand wash soap. Detailing brands with an established reputation don't make these as hand wash shampoos either. They are only made as pre wash shampoo for in foam guns or as a concentrated product to loosen bugs and other stubborn dirt and then clean with a real car shampoo.

This is because we just mentioned that citrus is a solvent/solvent. It is a strong agent that also dissipates and possibly leaves traces. This is because the most important thing in a hand wash is lubricant. There are several pre wash shampoos that you can put in your foam gun, also citrus based that can safely loosen all the dirt without leaving traces. After this you can use a pressure washer to rinse your car and it will be almost clean. This is because pre-wash shampoos are specially designed to stay on the paint and loosen the dirt without damaging it or leaving traces. They are not designed to be slippery, just to remove and loosen dirt.

In addition, the other chemicals that are in the detergent are formulated to clean kitchen items such as plates, pans, cutlery, and so on. They are mainly to remove food debris. The car shampoo is a completely different formula that is specifically made to get the dirt off your car. This can be such as oil, insect residue, salt, brine, road grime, and so on. So when you start putting a good car shampoo next to a dish soap and compare them you will find that the car shampoo cleans better with less product than the dish soap.

Scratches from detergent?

Dish soap will also cause scratches in your car. You will use dish soap to hand wash your car. However, dish soap cleans considerably less than a real car shampoo. Because of this, you will have to rub the same dirt several times to get it clean whereas with a real car shampoo, you probably only have to go over this once or twice before it is clean. Every time you rub the paintwork you make scratches, this is impossible to avoid. However, we are not necessarily talking about deep scratches that you can see from afar. But small wax scratches that make the paint look dull and ugly.

To keep these scratches to a maximum, it is important that you have a shampoo that allows your wash mitt to glide well over the paint. Because the dish soap is considerably less slippery than the car shampoo, you will also scratch a lot more paintwork during the wash.

So if you like having a clean car, but don't want to spend too much money on shampoo but also like your car to shine, then you are guaranteed to be better off with a suitable car shampoo. Having your car repolished because it has so many wax scratches after using detergent for a long time will immediately repay the cost of a car shampoo! You can also buy these in larger quantities, which means that a 5L can of professional car shampoo, for example, will last you for years and you can invest as little as €50.

These are the 3 points that (all) detergents had. Namely high pH, poor lubricant and citrus solvents. These 3 points alone ensure that as a detailer we would never recommend dishwashing detergent. But detergents consist of even more chemicals. For example, it can also cause you to potentially use a soap that is going to cause your chrome to fade or stain, plastics and rubber to fade, the acrylic windows in convertible roofs to no longer be translucent after a certain amount of time, stitching on convertible roofs to wear and break prematurely, residue from the soap could potentially burn into the car, and so on.

Chemicals in detergent

 As mentioned earlier, many detergents consist of various types of chemicals beyond citrus solvents. Therefore, it may be important to paint a picture of the reality of car varnish. A healthy and new varnish car paint that comes straight from the factory is about 60 µ (Micron) thick. That is 0.05mm thick, thinner than a sheet of paper. Adding to this the fact that due to strict regulations the varnish is also water based and is also significantly softer and less durable than varnish from the 2000s.

Generally, many people think that car paint can take some, but this is definitely not the case. In a gloss repair polish, the detailer removes an average of 4-5 µ. Now you can say, then my car can be polished 14x. That's never going to happen, so I don't have to worry. However, this is not true. Every year the varnish of your paint gets thinner and thinner. This can be due to the sun, scratches, washing, chemicals, and so on. Huge numbers of factors play into why your varnish gets thinner and thinner. Also, on edges, the varnish layer is thinner which means that the varnish is burned through there faster.

When a varnish begins to become too thin, it will begin to flake off, oxidize, begin to change the color layer, and so on. This process cannot be reversed without having the varnish repainted.

Why do we put dish soap in a stubbornly burned-on pan and let it soak in? So that the aggressive dish soap dissolves the dirt so you can clean it easily. Now imagine this harsh detergent on your sensitive paintwork. No, we'd rather not do that either. This is because it is guaranteed to corrode the paintwork; however, this does not surface immediately. It is mainly after prolonged use that you will be left with problems. Problems that can, of course, be perfectly avoided.

By the way, have you ever wondered why you have to rinse your dishes and the like so much after washing them with dish soap? This also gets worse when you use it on your car. This is because of the surfactants in the detergent. The amphiphilic organic compounds cause the detergent to be both “water-loving” and “water-hating,” which means it actually repels water. This makes it difficult to rinse and often leaves streaks on the paint. This immediately confirms to you that your paint is damaged.

Dried detergent no matter how small the layer may be will soak into the paint and damage it. When the sun is on it, even in extreme cases it can burn in. In addition, it can also cause you to get water spots, when these dry up and burn in they cannot be removed from the paint without sanding.

Conclusion on dish soap as car shampoo

As previously told, we are not car shampoo manufacturers or chemists. But we do have knowledge of car shampoos, detailing, basic knowledge of soap formulations, and a lot of experience in car washing. So, what exactly is the conclusion about using dish soap as soap to wash your car?

Want to use it one time quickly because you ran out of car shampoo and need to wash your car? Then you can use it, at your own risk of course. However for long-term use, it is anything but recommended. We assume that you will definitely wash your car every 2-3 weeks though. This means about 18 washes per year. If we assume that you would use about 50ml of car shampoo for each wash, then with a 5L bottle of Gtechniq GWash, for example, you would do 100 washes. Or in other words, 5 and a half years for only €64 at the time of writing this blog.

With this you have a professional, pH neutral, safe, good working car shampoo that we use all the time as professional detailers. With this you will save time, money, effort and worry by investing once in a can of specialized shampoo.