If you want your neighbor's cat to stop coming to your house, but don't want to leave traces, you can try the following methods: 1. **Smell repellent**: Cats are sensitive to certain smells. You can try spraying smells that cats don't like in your yard, such as lemon, orange, mint or vinegar. You can use diluted vinegar water or lemon water. 2. **Natural barriers**: Plant some plants that cats don't like, such as roses, chives or rosemary, to form a natural barrier. 3. **Sound repellent**: Use some natural sounds, such as wind chimes, leaves blowing in the wind, etc. Cats generally don't like continuous noise. You can try using some lightweight devices. 4. **Avoid attractants**: Check your yard for items that attract cats, such as food, water sources or comfortable habitats. Make sure there are no food scraps, garbage or water sources that attract cats. 5. **Use reflectors**: Cats are sensitive to strong light and reflections. You can place some shiny objects, such as old CDs, aluminum foil, etc. on the windowsill or in the yard to interfere with their vision. 6. **Water spray**: If your neighbor's cat frequents your space, you can use a water sprayer to gently spray it to create some fright when it enters your space, but make sure this method does not cause harm. 7. **Set up barriers**: Set up some safe barriers in obvious places, such as low fences or plants, to prevent cats from entering your yard. When using the above methods, please make sure to respect your neighbor's cats and avoid harming them. Most importantly, be patient when using these methods, it may take some time to see the results.