What should I pay attention to when washing the car? How to choose detergent?

As long as it is a neutral detergent! Regarding car wash liquid, many seemingly professional people will use terms that ordinary people can't understand to explain that household washing products such as washing powder and detergent can't be used for washing, because these washing products are highly alkaline and oily, and if used, they will be dull, leading to metal corrosion and damage to car paint. In fact, the person who said these words, whether he is a car wash expert or not, at least knows nothing about the principles of detergents and washing chemicals. Let's look at the ingredients of washing powder first. Although there are many brands of washing powder with different smells, advertisements make people feel that each family has its own secret recipe, but in fact, the main ingredients are nothing more than the following: sodium alkylbenzene sulfonate, sodium tripolyphosphate, sodium silicate, carboxymethyl cellulose, sodium sulfate, sodium carbonate and essence. It is certain that the washing powder is alkaline, because sodium silicate and sodium carbonate are both salts of strong base and weak acid, and when dissolved in water, hydroxyl ions will be dissociated, both of which are alkaline. However, please note that alkalinity does not mean strong alkali, and the PH value of washing powder 1% aqueous solution is only about 10, which is only a weak alkali! This little alkali has such a short contact time that if the car paint can't stand it, the car factory will really close down. It should be noted that paint is a polymer synthetic resin of polyurethane and polyacrylate, and its performance is much more corrosion-resistant than furniture paint! If the paint is really so afraid of washing with washing powder, it is estimated that there will be furniture-specific detergents on the market, but unfortunately there is not. Let's look at the detergent. The main components of the detergent are sodium alkylbenzene sulfonate, alkyl alcohol amide and sodium alkyl polyoxyethylene ether sulfate. It is a neutral, safe and non-corrosive detergent. People in the car wash industry say that if the detergent is too oily, it will wash off the bright wax on the car body and make the car paint lose its protective effect. That sounds reasonable, but: first, the main function of waxing is not to protect the car paint, but to brighten the freshly washed car body, that's all. Car paint is not as fragile as you think. You need wax that falls off when washing to protect yourself. Second, the car wax itself is not firmly combined with the car body, but only attached. Even if there is no detergent, any car cleaner will still wash off the car wax under the brushing condition after application. Moreover, even if the degreasing effect of detergent is strong, the function of any substance cannot be separated from the dosage. Since this detergent is considered to have great effect and strong detergency, why not use more! Those detergents with weak detergency can't clean the car if they are used less, and they will be washed off with emulsified wax if they are used more. Therefore, if there is a car cleaner for car washing, the owner doesn't care about the high price, just use it. If you care about the price, or if you only have other neutral washing on hand, you don't have to worry about the saying that the paint is damaged and can't be verified.