To gently prevent a neighbor's cat from entering your house without leaving obvious traces, you can try the following methods： ### 1. **Use odor to repel** -**Citrus smell**: Cats usually don't like citrus smell. You can put lemon peel, orange peel or spray citrus essential oils on the door or window sill. -**Vinegar**: The smell of white vinegar has a repelling effect on cats. Dilute the vinegar and spray it on areas where cats often haunt. -**Coffee grounds**: The smell of coffee grounds can also repel cats and sprinkle it near the door or window sill. ### 2. **Sound drive away** -**Ultrasonic equipment**: There are ultrasonic repellers specifically for cats on the market, which will make sounds that cannot be heard by the human ear but are uncomfortable for cats. -**Wind chimes or metal pieces**: Hanging wind chimes or metal pieces, the sound made when the wind blows may make the cat feel uneasy. ### 3. **Physical barrier** -**Anti-cat thorn pads**: Place anti-cat thorn pads (made of plastic or rubber) on the window sill or doorway. Cats will be uncomfortable when they step on it, but they will not hurt them. -**Grids or screens**: Install fine grids or screens to prevent cats from entering. ### 4. **Change the environment** -**Remove attractants**: Make sure your home does not have food, water or a comfortable place to rest that attracts cats. -**Planting cat repellent plants**: Plant plants that cats don't like, such as lavender, rosemary or mint, in the garden or balcony. ### 5. **Behavioral training** -**Water spray**: When the cat is close, you can use a watering can to gently spray water. Cats will gradually associate your home with unpleasant experiences. -**Noise fright**: Make sudden noises (such as clapping hands or tapping objects) when the cat approaches, but don't be overly frightened. ### 6. **Communicate with neighbors** -**Friendly consultation**: If you know the owner of the cat, you can politely explain the situation and ask them to take measures to limit the scope of the cat's activities. These methods will not cause harm to cats, and at the same time can effectively reduce the frequency of them entering your home.