If the thermos is sunken, you can burn it slightly with hot water. Because of the principle of thermal expansion and cold contraction, the thermos will recover a little.

If it's serious, use glass glue and sucker, apply the glass glue to the depression of the thermos cup, then press the sucker in the depression, and then pull it out when it's completely dry.

Using the viscosity of the glass glue and the suction of the sucker, the sunken position of the thermos cup can be forcibly pulled out. If these two methods can't restore the thermos cup, then the sunken position of the thermos cup can't be restored.

Advantages and disadvantages of stainless steel cups:

Advantages:

Stainless steel material, durable, beautiful and generous, long service life and diverse shapes.

Disadvantages:

1, stainless steel cups cannot be used to hold traditional Chinese medicine, otherwise it will be harmful to human body.

2. At present, most stainless steel materials on the market are stainless steel iron. Stainless steel cups contain chromium, which is a heavy metal. Corroded stainless steel cups will be released because the protective film is destroyed, which will cause harm to human body if they continue to be used.

3. You can't make tea. Soak the stainless steel cup with tea, cover it tightly and let it stand for 72 hours. After 72 hours, the stainless steel cup was opened and turned over, and it was found that the inner wall of the cup was obviously corroded. Some insiders also said that tea contains a variety of chemical components, and chemical reactions will occur when tea is made in stainless steel cups.