There is a saying in geomantic omen that dirty rags destroy windows and make money, which is easy to suffer from respiratory system and eye diseases.
As you said, there is no problem. The so-called Sha Qi in Feng Shui refers to the visible, and the reason why screens, potted plants, etc. turn evil into positive is to keep out. Your neighbor is invisible under normal circumstances, so don't worry.
Of course, you can talk to your neighbor and ask him to take it away, otherwise, it will be bad for him. The so-called dirty things are not obvious, which refers to this situation.