For example, watches, because there are many lights in the display cabinet where watches are displayed. These lights will heat up, take away moisture and dry the air index in the cabinet. A dry environment will tarnish the watch. Putting a glass of water can increase the humidity, keep the watch shiny and decorate it.
Jewelry, for example, needs nourishment. After all, jewelry depends on a certain amount of water to keep its luster. Just like human skin, it needs hydration in dry and hot weather. Then the primary purpose of putting a glass of water is to increase the humidity inside the jewelry counter, because there will be a projection lamp above the jewelry counter, the temperature will be higher after a long time of light irradiation, and the air humidity will evaporate quickly, which will dry the air inside the counter, and the dry air will make the jewelry surface rough, dry and discolored, so putting a glass of water in the counter can keep the air humidity, thus playing a role in protecting jewelry.