By constant remembrance of God and repetition of His Names the impurities of the heart are gradually washed away and the heart becomes purer and purer from day to day.
When the heart has become pure and stainless, waves of Vairagya will naturally arise in the mind and the attraction for sense-objects will automatically vanish.
Just as a mirror is freed from dirt and becomes clearer and clearer as it is rubbed with cotton, even so the mind gets purified and illumined by constant remembrance of and meditation on the Lord, and the soul from within shines forth all the more brightly through it.
Cited from "Kalyana-Kalpataru",
from "Disspassion" article by Jayadayal Goyandka