Precautions for using vacuum flask
Do not use the cup after opening for more than half a day. If the hot milk is placed in the cup, it is like a petri dish, which will change quickly and should be prevented. If you keep cold for a short time, there is not much doubt. Soda can't be filled with a thermos bottle, and it is dangerous to put the soda in a rigid container. As far as the degree of cleanliness is concerned, even if only boiled water is installed, the thermos cup needs to be cleaned once a day, otherwise the warm environment will cause the bacteria to multiply.