Shatkarma is a compound word consisting of two components: shat meaning 'six' and karma meaning 'art' or 'process'. The word kriya or karma is used in Hatha Yoga in a special technical sense regarding the techniques of cleaning. These practices, outlined by Yogi Swatmarama in the Haṭha Yoga Pradīpikā, are:

• Netī, nasal cleaning.
• Dhautī, cleaning of the digestive tract.
• Naulī, abdominal massage.
• Basti, colon cleaning.
• Kapālabhātī, purification and vitalisation of the frontal lobes.
• Trāṭaka, blinkless gazing.

More details

• Netī refers to nasal wash. This is the practice of using a neti pot to cleanse the nasal passages. A basic neti wash consists of purified water and non-iodized salt, to create a gentle saline solution. A demonstration of this practice is available through the website of the Himalayan Institute
• Kapālabhātī refers to skull polishing, and is a pranayama (breathing) practice intended to energize and balance the nadis, and the chakras. Specifically, it is a sharp, short outbreath, followed by a relaxation of the core that allows the body to inhale on its own.
• Naulī refers to intestinal cleansing. The practitioner stands with the feet about hip width apart, hands on knees, and body at about a 45 degree angle. The core is rotated internally by moving the abdominal muscles alternately in a clock-wise, then counterclock-wise direction.

References