Here are some ways to do this that won’t harm your cat and won’t leave obvious marks in your home. It’s important to note that when taking measures, try to use non-invasive, environmentally friendly and humane methods. You can also try to communicate with your neighbors to find a solution together: 1. Ultrasonic cat repellers • There are some small, solar-powered or battery-powered ultrasonic cat repellers on the market. These devices can emit high-frequency sounds that are inaudible to human ears but uncomfortable for cats. • When installing, try to hide them in flower beds or corners. The appearance of the device is not obvious, and it will not leave physical marks in the yard or doorway. 2. Motion-sensing sprayers • Some devices will automatically release a small burst of water mist when they detect an animal approaching. The water mist is an unexpected stimulation for cats and can make them leave quickly. • The nozzle can be installed in an inconspicuous corner, and the water marks left after spraying will evaporate quickly and will not cause lasting marks. 3. Temporary barriers or arrangements • You can use some movable decorations or plants to change the routes that cats often take, such as placing some plants with smells that cats don’t like (such as citrus plants, rosemary, etc.); • If it is a yard problem, temporarily installing some hidden mesh fences or decorative fences can also play a barrier role and is easy to remove, and will not leave long-term traces in the original environment. 4. Use commercial cat repellent (spray type) • Some cat repellent sprays are based on natural ingredients, and the smell has a repellent effect on cats. If the dosage is properly controlled, no obvious residue will be left. • It is recommended to spray on the border area or corners where cats frequently appear. After the spray dries, the smell will gradually dissipate and will not cause long-term impact on the environment. 5. Eliminate the triggers • Check whether there are food or habitats that cats like (such as garbage dumps, bird feeders, etc.) in the surrounding area to minimize the factors that attract cats to approach. • Keeping the yard clean and regularly changing the location of pet supplies can also reduce the interest of cats in staying. Warm reminder: • No matter which method you choose, make sure that it does not cause substantial harm to the animals, and try to keep the measures concealed so as not to cause discomfort to the neighbors. • If the situation persists, you can communicate with the neighbors calmly, let them know the problem, and seek ways to improve it together. The above methods are relatively mild, non-destructive and easy to restore to the original state. I hope they can help you.