What should I do if there are yellow stains on canvas shoes?

Brush with clear soapy white toothpaste. First, apply transparent soap to the yellowed area and choose a soft brush for cleaning. After cleaning, you can apply appropriate toothpaste for better effect. Choose the soft brush head to brush again. After brushing, rinse with water. Then wrap it with toilet paper and put it in a cool and ventilated place to let it dry naturally.