Purification Mantra in Hinduism
Pavitra Mantra (Sanskrit: पवित्र मंत्र) is a Sanskrit Mantra chanted during Puja for purification in the tradition of Hinduism. It is also called as "Snaana Mantra" or "Shuddhi Mantra".
Description.
Pavitra Mantra is mentioned as the 12th verse in the 80th chapter of the "Patalakhanda" in the Hindu puranic text Padma Purana. 
 ;templatestyles src="Template:Blockquote/styles.css" / ;"ॐ अपवित्र: पवित्रो वा सर्वावस्थां गतोपि वा। य: स्मरेत् पुण्डरीकाक्षं स: बाह्याभंतर: शुचि:।।"
— In the Mantra, the name of Lord Vishnu is mentioned as "Pundarikaksha". The literal meaning of Pundarikaksha is one with lotus-like eyes. The mantra starts with the sacred letter "Om" which signifies the symbol of ultimate truth Brahman in Hinduism.
The meaning of the Mantra is philosophical and symbolic. It is about the purification of inner and outer self. 
In the Mantra, it is said that if one is impure or sacred or even in all other situations, then remembering the name "Pundarikaksha" which is another name of "Lord Vishnu", one becomes purified from within as well as from outside self. 
Method for practice of the mantra.
During the utterance of the mantra for self purification, some holy water is taken in the left hand covering it with the right hand and after chanting the mantra, the holy water is sprinkled the on the head and the body. Similarly before starting a "Puja", the holy water is consecrated by splashing it on oneself and on the worship materials.