Required materials: rag, warm water and white vinegar.

1. First, wash the mat twice with a rag dipped in warm water.

2. Then take a basin of warm water and pour it into the white vinegar, and stir well.

3. Wipe the mat twice with a rag dipped in white vinegar.

4. Then pour a pot of warm water into the toilet water and stir well.

5. Then wipe the mat twice with a rag dipped in toilet water.

6. Finally, just dry the mat in the sun.