This information was found on baringtheaegis.blogspot.nl
The concept of purification — katharmos — is linked to miasma: ritual pollution. I have written about this before, most notably here, and here. A summary of the content of those links, and then we’ll get to the act of purification.
Within Hellenic practice, miasma describes the lingering aura of uncleanliness in regards to a person or space through which contact is made with the Gods. Miasma occurs whenever the space or person comes into contact with death, sickness, birth, sex, excessive negative emotions and bodily fluids. It also comes from a lack of contact with the Hellenic Gods. Not the actual acts of dying, sex and birth cause miasma but the opening up of the way to the Underworld (with births and deaths) as well as contact with sweat, blood, semen, menstrual blood and urine pollutes us. Miasma is an incredibly complicated and involved practice and it’s often misunderstood. The most important things to remember about miasma is that it holds no judgment from the Gods, and that everyone attracts miasma. It’s a mortal, human, thing.
The practice of purification is called katharmos (Καθαρμός). The process of katharmos is elaborate because it not only involves the physical but also the emotional, mental and spiritual. Katharmos is devotional. It not only helps you get in a ritualistic mood, it prepares the room and your body for it. Even if you do not understand the use, it’s a vital part of Hellenistic worship, and I encourage everyone to practice it.