1. Soak clean water in alkaline water for several hours and then brush it carefully with a toothbrush;

2. Soak the sleeves in water for a while, lift them up and apply a layer of toothpaste, then leave them for a day or two and brush them carefully with a toothbrush.

Tips: When buying a water jacket, try to choose a brand with good quality and good reputation, so that the chance of it turning yellow will be greatly reduced.