First of all, look at the properties of silver. The chemical properties of silver are very stable, but stability does not mean that it does not react. Silver and oxygen can generate silver oxide, which is brown, unstable in chemical properties and easy to decompose. Silver can also react with sulfur to produce silver sulfide, which is black in color and relatively stable in chemical properties.
There is a small amount of sulfide in the air where we live. When you wear silver ornaments for a long time, the silver ornaments come into contact with sulfide in the air, and with your body fluids, which react together to produce silver sulfide, so you can see that the silver ornaments on your body are black.
When watching TV series, before seeing the emperor eat, the servant will try the dishes with silver needles in advance, and the emperor himself will eat with silver chopsticks. If someone poisons food, silver needles and chopsticks will turn black quickly, because most of the poisons used for assassination in ancient times are arsenic, and because of the backward manufacturing technology, a lot of sulfide will remain in them. At this time, silver and sulfur reacted to make silver products black, reminding people at that time that this food was poisonous. Now when scientists are studying the cause of death of Emperor Guangxu, not everyone has found that the sulfur content in Emperor Guangxu's relics has far exceeded the normal standard value. It is preliminarily concluded that Guangxu died of poisoning.
However, don't worry if the silverware is black. Here is a trick to teach you how to remove silver sulfide without damage. Put silverware, aluminum and alkaline water together, heat and boil, and let them react for a period of time. Because of the replacement reaction, the silver in silver sulfide will be replaced and become simple silver, thus eliminating silver sulfide and black at the same time.