The newly-purchased thermos doesn’t keep warm for a long time. What is going on? Is there a problem with the quality of the vacuum flask? In fact, it's not all thermos cups that have such problems are quality problems. The correct use of the thermos cup for the first time has a great relationship with the insulation effect of the thermos cup in the future. If it is used incorrectly for the first time, it will have a great impact on the insulation effect of the vacuum flask. So how should this newly bought cup be used correctly?

First of all, after disassembly, it is best to use boiling water first, or add some detergent to scald it several times for high temperature disinfection. Before use, in order to have a good heat preservation effect, it is best to preheat it with boiling water or cold water or let it cool for about 10 minutes. The first time you add water to the thermos cup, it should not be too full, so as to avoid the boiling water overflowing and scalding when you tighten the lid. The first time you use the thermos cup, its insulation performance is definitely very good, so be careful when drinking hot drinks with the thermos cup, and don't make a mistake in judgment and burn.

For some carbonated beverages such as milk, dairy products and fruit juices, it is not advisable to store them in a thermos for a long time. This will affect the drink back and forth, and will damage the thermos. After the thermos is used, it must be cleaned in time. It is best to use a soft cloth and a food cleaner diluted with warm water.

The inside of the stainless steel vacuum flask may sometimes have some red rust spots due to iron and other substances in the contents. At this time, it can be soaked in warm water with salt or diluted vinegar for a period of time, and then rinsed with boiling water. If you need to make tea regularly (2-3 days) to clean the tea stains, use salt or toothpaste.