The ashes resulting from Vedic rites in fire shall be smeared over the forehead at the end of the rites. Since the ashes are purified by the mantras the rite itself takes the form of the ashes.
Hence, applying the ashes is tantamount to assimilating the sacred rite in one’s own Ātman. Bilva twigs shall be burnt repeating the Ātma mantra of Aghora
Shall be burnt first and then the twigs of Śamī, Aśvattha, Palāsa, Vaṭa, Āragvādha or Bilva shall be burnt. The ash resulting therefrom is also Śivāgnija.