Most people are not aware that negative energies exist and can influence us on all levels of our existence.

I realize how difficult it may be for many to acknowledge the interference in our life of something we can not understand and most of the times not see. We live in changing times. As the energies in our dimension raise in vibration there is an increasing battle between Light and Dark.
Places they really like to hang out are Prisons, Hospitals or bars and nightclubs.
Negative energies left over and taking form as Demons, Poltergeist, Negative Entities, Negative Spirits, Lost Spirits… negative attachments.
In order for these energies (Spirits, Souls) to survive them most often attach to a human host.
There are many reasons why they missed the move to the other side and they may have been stuck here or with you for a long time. There are plentiful of different kinds of entities or negative spirits. The ones just simply lost and missed the move on, like from an accident, or just not ready.
The ones left over here from child molesters, women abusers, drunks, murderers and the list goes on.
Most of them are very glad and thankful when showed and helped to move on to the light and there proper dimension where they need to go. There is the exception to the rule and it really needs knowhow and expertise to convince them to let go and move on. But these are very rare and in the end they never desire or can come back.
Smudging, ringing Bells, Sound, Reiki are great ways to get rid of stagnant and unpleasant energies and energize with positive and good energies.
For sure it is not the way to go after Demons, Entities or negative Spirits.
You can do more harm then good.