Pranayam, that is mentioned in Gita (controlling of pran and apan), cleanses the chakras or nadis, the energy plexes in human body. Thakurji has said that we should do pranayam. Do pranayam with surrender. There is other stuff out there, like many many types of meditations that open up your chakras. Chakras hold memories and attachments and Gita says let go of your attachments and leave all the subjects that bother you and only think about HIM. Its a vast subject
But truth of the fact is that nothing gives more wisdom, peace and love than HIS name. Bhakti and love for him is the answer for everything.
Hare Krishna is actually not a Mantra of Krishna but its an stimulation of Throat-Vishuddhi and Solar Plexus – Manipur Chakras along with Anahad.
Vishudhdhi mantra is Hum हं and Manipur mantra is Rum रं which make Hari or Hare
Krishna is supposed to be related to Anahad and Vishudhdhi combined. The sound of Ka क, क्र, क्लीं, कृ।
Kali, Hanuman, Krishna, even Christ is related to these chakra.
same case with Rama… thats why chanting Hare Rama _ Hare Krishna booms the heart chakra and we feel awesomeness.
its all activation and stimulations of chakras.
Similarly, Ham Ham Haank Det kapi Chanchal… Bajrang Baan is related to Vishudhdhi chakra… which is responsible of observations of surroubding. once you are aware… no bhoot pisaach will come to you.