Purifier in the world is Wisdom - Bhagavadgita

Nahi Jnanena sadrusham pavitram iha vidyate | Tat swayam yoga samsiddhaha
kalen atmani vindathi || 4.38 ||

Meaning:

*"Certainly, there is no purifier in this world like 'Knowledge. ' He who is
himself perfected in YOGA finds it in the Self in time."*

My understanding:

Through wisdom (Jnana) only one can get purified, from his Karmas and no
other way is found in the world other than this. By practicing some
meditation practices, by cleaning chakras, by daily dedicated work towards
improving ourselves, we can attain Jnana( self-realization) on one or the
other day. There is no time limit, if we are really ready to get it.

Comments of Swami Chinmayananda:
*

So glorious is the result of Self-realisation that Lord Krishna explodes in
enthusiasm and cries: "VERILY THERE EXISTS NOTHING IN THIS WORLD MORE NOBLE
AND SACRED THAN SELF-KNOWLEDGE." Just as to a drowning man there is nothing
more precious than a life-belt, so too, to the deluded ego there cannot be a
greater possession and a nobler endeavour than the acquisition of
'Knowledge' of its own Real Nature.

The Knowledge of the Self can be attained in one's own bosom when one has
gained in oneself a full "MASTERY IN Yoga" --- when one has sincerely and
diligently practised the above-mentioned twelve Yajnas and gained a complete
self-mastery through them. This mastery of the Self over the flesh is not
given by any teacher. The traditional story of a teacher spiritualising a
student by his touch is a myth; it is impossible. Had it been so, in the
presence of such a perfect Prophet like Krishna, Arjuna could have attained
--- especially when the Lord felt such a great friendliness and love towards
him --- in a wink, all the spirituality needed to become a God-man.

Many devotees have, from time to time, wasted their chances and brought
dishonour to their noble teachers, because they expected their Gurus to
impart their acquired Wisdom to them, their Chelas (disciples), for the
physical services rendered or the intellectual support given. Many of the
existing seekers are, today, thoughtlessly squandering away their noble
opportunities by vainly waiting for this cheap and ready method of
purchasing God-hood! Let them be warned that, in spite of such
glorifications of some Gurus available in the market and sold at some
Ashramas in this country, it has no scriptural support. Here, Krishna, in
all love, plainly tells the truth to Arjuna that he has to purify himself (
Swayam) and then he himself will realise the Truth "in good time" (Kalena).

No definite time schedule is promised for Perfection to manifest. It is only
said that he who is practising sincerely and devotedly, all the twelve
different subjective-Yajnas that are described earlier, will attain the
necessary growth within, and will "IN GOOD TIME" come to experience
the Self, the Beatitude-of-Perfection, the State of God-hood. IN GOOD TIME (
Kalena) --- This does not mean either immediately, nor does it promise us
the Supreme only after trillions of impossible years.
*