There are two types of colored glass bottles, one is primary color glass and the other is sprayed glass.
Primary color glass, as the name suggests, is the same color at the beginning of molding, and will not be changed later.
Spray glass, that is, glass with spray paint on the surface.
So how to distinguish primary color glass or sprayed glass?
The answer is very simple, use a sharp object at your hand, such as a knife, key, etc., to rub hard on the colored part. If the paint can be scraped off, it is sprayed; if it cannot be scraped off, it is the primary color.
As for whether white glass is frosted or sprayed, it is also very simple. The frosting effect will disappear when exposed to water. As long as the surface of the bottle shows a transparent effect after being wet, then it is frosted glass.
You can also tell if there is no water. Because the frosted glass is corroded, the surface will have a sandy feel, which is obviously different from the smooth glass, and it can be distinguished by this.