How to clean Tonkinese cat tear stains:

1. Clean the eye area regularly. Clean the cat's eye area carefully. It is best to soak a clean towel with warm water every day, wipe the cat's face, and remove any remaining tears or eye droppings. If your cat has excessive eye secretions, you can clean the cat's eyes with sterilizing eye drops for a week.

2. Clean your ears regularly. Some of the nerves in the cat's ear canal and face are intertwined, so ear mites can infect the eyes, causing eye inflammation, redness and swelling, and over time, tear stains will form. Be sure to clean your cat’s ears regularly to prevent ear mites.

3. Use starch and boric acid powder. If your cat's tear stains are serious, you can also mix starch and boric acid powder with water, stir it slightly, and gently brush it on the area with tear stains, and then remove it after it dries. If you insist on using it for a few days, you will have unexpected effects.

4. Let the cat drink more water. Severe tear stains in cats may be caused by overheating because they often do not drink water. Severe overheating will lead to the appearance of tear stains, so cats should be given more water.

5. Feed fresh fruits and vegetables. You can usually feed it an appropriate amount of fresh fruits and vegetables, such as apples and pears, which are rich in vitamins and water to supplement certain nutrients.