How to clean the scale of the thermos liner?

After using the thermos for a long time, be careful to clean the liner. There are several ways to do this:

1. Add 50g of baking soda to a cup of water, pour it into the bottle and gently shake it. The scale can be easily removed.
2. Place a small amount of tea in a thermos bottle, then pour in the boiling water and cover the cap. After half an hour, the scale in the bottle will fall off under the action of theophylline. Even soak for a few times until it completely falls off.
3. Use paper towels to make two small spherical paper balls, then put them into a thermos bottle, inject hot water into them, cover the cork, and shake them sideways while shaking. After a few minutes, you can remove the scale inside the bottle. .
4. Put a little salt in the hot water bottle, then fill it with hot water, soak it for 10 minutes, then rinse it with water several times to remove the scale.
5. Heat the vinegar and pour it into the thermos bottle. After standing for a few hours, pour out the vinegar and wash it with water. It can also be descaled.
6. Put a little rice (or egg shell, chopped), add a little water, cover the stopper, shake for about 2 minutes, the scale will fall.