Cleaning: Wash, rinse and dry the vacuum flask before using it for the first time. The flask may be washed in a dishwasher. If you wash it by hand, always add bicarbonate of soda or washing-up liquid in the water
Good to know: — Pre-heating the flask with hot water (or cooling it with cold water) makes sure the contents retain the desired temperature for longer. Never use a vacuum flask in a microwave oven, an oven or freezer. — Do not keep carbonated (fizzy) drinks in the flask. The build-up of pressure can make the cork explode with considerable force. The same thing may happen if sugary drinks in the flask are exposed to heat, as heat sets the fermentation process in motion. — If possible, avoid using the vacuum flask for baby food and for drinks made with hot milk. Bacteria can develop rapidly in the heat and set the fermentation process in motion. If you do keep milk or baby food in the flask, make sure this is only for a short time, and always clean the flask carefully afterwards.