2. Salt+alcohol combination

First, use salt granules to scrub the inner wall, and then disinfect it with 75% medical alcohol, which can eliminate bacteria and residual odors. ‌‌

1. Baking soda/citric acid dissolution method

Dissolve 15g of baking soda or citric acid in hot water, soak for 30 minutes, and rinse to remove mineral deposits. ‌‌

2. Lemon salt physical descaling

Cut half a lemon and dip it in salt to directly wipe the cup wall. Acidic substances and salt particles rub together to remove dirt, which is a natural solution suitable for situations without cleaning agents. ‌‌