Now the thermos vacuum flask is more and more accepted by the masses, because it is not only novel in style, but also particularly convenient and practical, and is the best choice for many promotional gifts. But as a promotional gift, if the price is too expensive, the cost will be high; too cheap, and afraid of poor quality. In fact, as long as you can use it and use it well, the insulation effect of cheap thermos vacuum flasks can also be very good.
First of all, don't rush to wash with cold water after you get a new thermos vacuum flask. You should pour half of the boiling water into the thermos vacuum flask and shake the thermos vacuum flask 7-8 times. Don't open the lid first. Stand the thermos vacuum flask on the table for a few minutes to ten minutes. When you feel the inside of the thermos vacuum flask is uniformly heated, pour water out and wash it several times with hot water. After this operation, you will find miraculously that the insulation effect of the thermos vacuum flask is much better than that of the same type of thermos vacuum flask at the same price.
Secondly, in the process of use, as light as possible, do not shake and knock, which will damage the insulation of the thermos vacuum flask. When using, try to drink hot water and cover the lid. Don't always keep it open.