Viboothi , also called Bhasma (ash), Thiruneeru, is a word that has several meanings in Hinduism.Generally, it is used to denote the sacred ash which is made of burnt dried wood in Agamic rituals. Hindu devotees apply vibhuti traditionally as three horizontal lines across the forehead and other parts of the body to please the gods. Vibhuti smeared across the forehead to the end of both eyebrows is called Tripundra.
The great saint Thiru Gyaana Sambandar did many wonders with Vibhuti and he expounds the greatness of Vibhuti in one of his Pathigams called "Thiruneetru Pathigam" as follows:
Mandhira maavadhu neeru / Vaanavar meeladhu neeru
Sundhara maavadhu neeru / Thudhikkap paduvadhu neeru
Thandhira maavadhu neeru / Chamayaththil ullaadhu neeru
Senthuvar vaayumai pangan / Thiruaalavaayaan Thiruneerae
("Mantra is the ash; Higher than heavenly people is the ash; Beauty is the ash; Praised is the ash; Technique is the ash; In the religion is the ash; The Lord of Thiruaalavaay (Lord Sundareshwarar, Madurai) who share the body with the red lipped Parvathi - His Holy Ash.)
Panchakshara mantra and the above Pathigam are generally recited by devotees while smearing Vibhuti. Winning the Jains in the challenge on fire Thirugnana Sambandhar sang the above marvelous hymn Thiruppaachuram explaining the king and the world the limitless grace and glory of Lord Shiva and won the Jains in the water challenge. Thiru Gyana sambandar won the Jains and re-converted the king and his people back to Shaivism by Vibhuti reciting the above Pathigam. Vibhuti of Vaitheeswaran Koil and Thiruchendur Murugan Temple is famous for curing many incurable diseases.