Soaking and cleaning with baking soda or oxygen bleach can effectively remove discoloration. Please follow these steps:
Soak method:
1. Fill a bowl with hot or lukewarm water and add baking soda or oxygen bleach to dissolve.
(Beware of spills when using oxygen bleach)
2. Soak the lid and leave it until the hot water cools.
3. Discard the water and rinse the parts thoroughly.
4. Wash with dish soap, rinse well, and allow to dry completely.
For stubborn stains, gently scrub the mesh with a toothbrush to help remove residue.