There are vibrations everywhere. The whole word is just vibrations. Every object is a vibration. So there may be some negative vibration that can come towards you and you may feel a little discomfort.
If someone abuses you, then doesn't your mind get scattered and lose its focus? Doesn’t it happen to you? A simple solution was found by our ancient people. They have said that waving or sprinkling some salt near the body removes these negative vibrations. Even in foreign countries when people are feeling a little disturbed they go and sit on the beach, or near the ocean. Do you know why? It is because the salty air cleans and energizes their consciousness. That is why when they sit by the beach they feel better. Just by using salt and water, you can cleanse your subtle aura. Nothing more is required than this.
There are a lot of superstitions and false beliefs like holding a baby upside down in temples, or burying a child in sand for a minute or so. All these are very wrong and should not be done. Our society has many such wrong beliefs and there is absolutely no mention of this in the scriptures. It is mentioned very clearly in the scriptures that anything that does not appeal to your intellect or anything that does not appear practical and appears to be a wrong should not be done at all. The Sanatan Dharma (another name for Hinduism from the ancient days) is against such superstitions. But such superstitions have crept into all religions. We have to remove these superstitions and adopt only good practices.