How to recover the heat preservation cup when it is not warm

1. Wipe the cup mouth clean
Open the cover of the thermos cup, take a clean paper towel, wipe the mouth of the thermos cup clean, and completely wipe off the water stains.
2. Wrap the tape twice
Take a roll of black tape and wrap the tape around the mouth of the cup for two turns.
3. Cut off the excess tape
Cut off the excess tape with scissors, pour hot water into the thermos, and cover it, so that your thermos can extend the heat preservation time.