This process of purifying the mind is also recommended by Lord Caitanya; He says that one should chant Hare Kṛṣṇa. He says further, paraṁ vijayate: "All glories to Śrī Kṛṣṇa saṅkīrtana!" All glories are given to the chanting of the holy names of Kṛṣṇa because as soon as one begins this process of chanting, the mind becomes purified. Ceto-darpaṇa-mārjanam: (CC.3:20:12) by chanting the holy name of Kṛṣṇa one is cleansed of the dirt that accumulates in the mind. One can purify the mind either by the breathing process or by the chanting process, just as one can purify gold by putting it in a fire and fanning it with a bellows.
(Srimad Bhagavatam------3:28:10------purport).

One must be very serious about self-realization and the practice of austerity. Unfortunately, the people of this age of Kali do not even know the meaning of austerity. Under these circumstances, the Lord has appeared as Śrī Caitanya Mahāprabhu to bestow upon the fallen souls the easiest method of self-realization, technically called ceto-darpaṇa-mārjanam -, cleansing of the dirt from the core of one's heart. This method is extremely simple. Anyone can chant the glorious kṛṣṇa-saṅkīrtana—Hare Kṛṣṇa, Hare Kṛṣṇa, Kṛṣṇa Kṛṣṇa, Hare Hare/ Hare Rāma, Hare Rāma, Rāma Rāma, Hare Hare. In this age there are different forms of so-called advanced scientific knowledge, such as anthropology, Marxism, Freudianism, nationalism and industrialism, but if we work very hard under their guidance instead of adopting the process practiced by Nara-Nārāyaṇa, we shall waste our valuable human form of life. Thus we shall certainly be cheated and misled.
(Srimad Bhagavatam------5:19:9------purport).

Śrī Caitanya Mahāprabhu's movement consists of spreading kṛṣṇa-saṅkīrtana. Paraṁ vijayate śrī-kṛṣṇa-saṅkīrtanam: "All glories to the Śrī Kṛṣṇa saṅkīrtana!" Why is it so glorious? This has also been explained by Śrī Caitanya Mahāprabhu. Ceto-darpaṇa-mārjanam:- by the chanting of the Hare Kṛṣṇa mahā-mantra, one's heart is cleansed. The whole difficulty is that in this age of Kali there is no sattva-guṇa and no clearance of the heart, and therefore people are making the mistake of identifying with their bodies. Even the big philosophers and scientists with whom we deal are practically all under the impression that they are their bodies. The other day we were discussing a prominent philosopher, Thomas Huxley, who was proud of being an Englishman. This means that he was in the bodily conception of life.
(Srimad Bhagavatam------8:5:23------purport).

As explained by Śrī Caitanya Mahāprabhu (Śikṣāṣṭaka 1):
ceto-darpaṇa-mārjanaṁ bhava-mahā-dāvāgni-nirvāpaṇaṁ
śreyaḥ-kairava-candrikā-vitaraṇaṁ vidyā-vadhū-jīvanam
ānandāmbudhi-vardhanaṁ prati-padaṁ pūrṇāmṛtāsvādanaṁ
sarvātma-snapanaṁ paraṁ vijayate śrī-kṛṣṇa-saṅkīrtanam
(CC.3:20:12)
"Glory to the Śrī Kṛṣṇa saṅkīrtana, which cleanses the heart of all the dust accumulated for years and extinguishes the fire of conditional life, of repeated birth and death. This saṅkīrtana movement is the prime benediction for humanity at large because it spreads the rays of the benediction moon. It is the life of all transcendental knowledge. It increases the ocean of transcendental bliss, and it enables us to fully taste the nectar for which we are always anxious."

(Srimad Bhagavatam------9:1:17------purport).

When discourses on kṛṣṇa-kathā take place between a liberated spiritual master and his disciple, others also sometimes take advantage of hearing these topics and also benefit. These topics are the medicine to stop the repetition of birth and death. The cycle of repeated birth and death, by which one takes on different bodies again and again, is called bhava or bhava-roga. If anyone, willingly or unwillingly, hears kṛṣṇa-kathā, his bhava-roga, the disease of birth and death, will certainly stop. Therefore kṛṣṇa-kathā is called bhavauṣadha, the remedy to stop the repetition of birth and death. Karmīs, or persons attached to material sense enjoyment, generally cannot give up their material desires, but kṛṣṇa-kathā is such a potent medicine that if one is induced to hear kṛṣṇa-kīrtana, he will certainly be freed from this disease.

(Srimad Bhagavatam------10:1:4------purport).