Purification is the act of removing contaminants from a person or object. This can either mean cleansing evil spirits or filtering out materials within a substance (ex. reverse osmosis in the purification of water). In the former case, this can be seen as a form of Soul Manipulation or Spiritual Healing and can be used as a counter to Possession. Purification can also be used to remove status effects.
Type 1: Material Purification - Material purification is a form purification that removes poisons, pollutants, and materials from a certain object or substance. An example of this would be melting the ore of a metal to get its pure form or using reverse osmosis to purify water.
Type 2: Spiritual Healing - This form of purification cleanses the body and mind of evil spirits. This can either involve the removal of evil spirits, the removal of curses, or simply getting rid of dark energy. Some examples include Celebi using its power to purify shadow pokemon, Algol creating Soul Calibur out of shards of the cursed Soul Edge, or Mung Daal using a treadmill to exorcise a demon chicken that possessed Chowder.
Type 3: Removal of Status Effects - This form of purification cleanses those of status effects, including poisons, paralysis, confusion, sleep, and various other status effects. Examples are usually found in items such as Full Heals in Pokemon, Senzu Beans in Dragon Ball, and Remedies in Final Fantasy, but this can apply to characters who can remove status effects such as Aqua of Konosuba, Arle Nadja (with the spells Purifa and Condia), and any pokemon that can use refresh and rest.