The munis completly smeared in Holy Ash. The Lord who burnt the three forts by His graceful smile, who burnt the dhEvA of desire with a wink of His eye, who dances enjo of His eye, who dances enjoying in the Self when the creations are reduced to ash before the regeneration that Lords holy blessing substance is the Holy Ash. The three adorable rated Holy Ash being kaRpam, an^ukaRpam, upakaRpam and unacceptable being akaRpam, one should accept the first three those purifies one from the flaws like desire.
When the cows that give the holy five substances for the Lord to get anointed are about to send out accepting that with the gomaya mantra , in the sacred fire grown for Lord shiva with the shiva mantra praised by the celestial bodies putting thus accepted cow dung saluting the Holy Feet of the Three-eyed Lord, the Holy Ash that results is the chaste kaRpam.
Bringing the dung that is dried in the forests, powdering it, wetting with the water of the cows, with the aththira man^dhiram casting it and then putting in the ritual fire and taking the properly burnt Holy Ash is the an^ukaRpam.
Other than ash from the forest fire, fire in the cow yard and a few such ashes, making balls out of the dung with the water of the cow chanting the holy mantras and then burning in the ritual fire and the Holy Ash thus obtained is called upakaRpam.
Thus taking the Sacred Ash humbly chanting the shiva mantra the slaves of the Lord adorn themselves. The Holy Ash the fame and fruit of which very big to explain and that makes good for the devotees who wear with respect kindles the spiritual progress. The munis wear this holy substance praising the God. Let the Holy Ash and its glory as found by the muzu n^IRu pUchiya munivar stay in the mind.
This chapter in periya purANam describes in detail how to prepare the Holy Ash and how to wear it.
1. thirun^IRRup padhikam