Fire is believed to reduce all substances to their primal state of purity. Hence, bhasma or ashes have always been considered as sacred by certain sections of the Hindu society, especially the Śaivas and the Śāktas (followers of Śiva and Śakti or the Divine Mother).
Bhasma derived from the Vedic fires is called ‘Śrauta-bhasma.’ It is to be taken out of the fire when the Vedic ritual is in progress and applied on the body. That derived from the fire lit up during a ritual performed as per the directions of smṛtis (secondary scriptures like the dharma-śāstras) is called ‘smārta-bhasma.’ If the fire is kindled by the Aghora-mantra (a mantra describing the aghora or non-fierce aspect of Śiva) with the wood of the bilva tree (Aegle marmelos), the ashes are called ‘śivāgni-bhasma.’ This bhasma is considered to be extremely sacred and capable of destroying sins as also ritual impurities.
Wearing a ‘tripuṇḍra,’ a mark of three lines on the forehead with bhasma, using the fingers on the right hand (the thumb, the middle finger and the ring finger) is considered a must for all the devotees of Śiva. These three lines are supposed to represent: the three Vedas (Ṛg, Yajus and Sāman); the three syllables (a, u and ma) of Om; the three guṇas (sattva, rajas and tamas); the three śaktis or powers (kriyāśakti, icchāśakti and jñānaśakti) of Devī or Divine Mother; the three pressings of soma juice in Somayāga (prātassavana, mādhyandinasavana and tṛtīyasavana) and so on. The whole idea seems to be to bring into one’s mind, various religio-spiritual concepts so as to feel pure and elevated.
Bhasma may be smeared over other parts of the body also, often to the accompaniment of appropriate mantras, thus purifying both the body and the mind. This is sometimes called bhasma-snāna or bath with bhasma.
Among the liṅgāyats (śaivites of Karnataka State) bhasma-dhāraṇa or applying the tripuṇḍra of bhasma on the forehead is considered as an important act of practice classed under ‘aṣṭāvaraṇas.’ (See AṢṬĀVARAṆAS.) According to their philosophy, bhasma is really that which burns up all illusions and paves the way for the intuition of the inner Self. The ashes are only an external and gross symbol of the process.
Bhasma as consecrated ash is used for ritual purification (like the water of the Gaṅgā river) of objects defiled by the touch of undesirable (or sinful) persons or animals etc., for protection against inauspicious things or evil spirits or even for purposes of sorcery and magical rites.
Bhasma has to be prepared by burning cowdung cakes in fire with appropriate mantras. The process has been described in the Bhasma-jābalopaniṣad, one of the minor upaniṣads of the Śaiva cult.