Ash on Shivas body.
Vibhuti is the sacred ash used in religious worship in Hinduism. The main ingredient of Vibuthi is a special kind of wood. It is burned in a sacred fire (Homa) to form white ash.
Vibhuti smeared across the forehead to the end of both eyebrows is called Tripundra.
It serves as a reminder to the believer to cast away selfish and worldly desires that wrap the self in maya, meaning worldly illusion and distractions, and calls to mind the legend of how Shiva burned Kama (the god of desire) to ashes when Kama attempted to break Shiva's meditation.
Normally, worn along with red tilaka(red dot). Vibhuti relates to Shiva and Red tilaka to Shakti. It is a constant reminder that Shiva and Shakti form the universe and everything is into being through, the union of Shiva and Parvati.
This form of Lord Shiva symbolizes the transcendental aspect of his nature and indicates that his presence is much higher than this physical phenomenon.
The ashes on the Lord's body is cemetery ash, which points to the philosophy of the life and death and shows that death is the ultimate reality of the life.
Most things in the universe reduce to ashes when burned and this aspect of nature is suggested by the ash-smeared appearance of Lord Shiva, who is held to be the God of destruction in Hindu mythology.
The Lord is beyond the cycle of birth and death.