The car shines after polishing, but this is a purely aesthetic issue. The main thing is that polishing compounds block the path of moisture and harmful impurities, which means they serve the body faithfully. Simply applying a polishing compound to a dried body is not enough. The wax films themselves (polishing compounds are usually made on a wax basis) almost always matte and in order for the car to sparkle and shine in the sun, you need to work hard to polish the applied composition. The mechanics of this process are as follows: polishing with a soft cloth (flannel is best), we rub the composition into the pores and microcracks, simultaneously smoothing the surface film. The heat generated during rubbing melts the surface, and the abrasive particles included in the polishes smooth out the existing irregularities. Thus, a protective layer is created on the surface of the body, which serves as a reliable barrier for oxygen, water, ultraviolet rays, cleaning solutions, etc. trying to penetrate it.
If the body is regularly washed and polished, the car pays off a hundredfold. Firstly, the body lasts longer, and this is cost-effective. Secondly, the aerodynamic qualities of the car are improved by reducing friction, and therefore fuel consumption is reduced. Thirdly, dirt and water, having no grip on the surface, roll off, and the car gets less dirty. These are only a few of the advantages of polishing, and the list can be continued.
Polishing agents are divided into "Polishes for new coatings", "Polishes for weathered coatings" and "Polishes for old coatings". Since new coatings are smooth, shiny, without scratches and microcracks, the role of the coating is to obtain a strong protective film. It usually withstands several (five-six) washes, repels fashion well, in short, provides such conditions that the condition of the paintwork is not disturbed.
Time passes, and you suddenly notice that no amount of effort applied during polishing provides the same shine. It seems that the body has developed immunity to "Polish for new coatings". Usually this state occurs after 2-3 years. Adjustments to the terms can be made by operating and storage conditions. The loss of the former shine is nothing more than the result of oxidation and the beginning of the destruction of the surface layer of paint. Of course, without abrasive particles in the polish, the resulting film cannot be removed from the surface of the body. "Polishes for weathered coatings", in addition to all the necessary components to provide a protective film, also contain a soft abrasive. It is the main cleaner. Having treated the body with this composition, having achieved the main goal - removing the oxidized layer, you can use "Polish for new coatings" again to fix what has been done.
When polishing a car body, you should remember that it is necessary to obtain a non-sticky, smooth, shiny protective film.
You won't get it if the body is poorly washed, if the composition is applied in a thick layer, if it is over-dried or under-dried. The instructions for the product stipulate the conditions of application and polishing. Following them, you will get a surface that will not have streaks, traces of touch, and dust will not stick to it.
(Original source is on the resource: vazbook)