Ashtangasamgraha 28.65

28.65

āturāṅgulamānena tannetraṃ dvādaśāṅgulam |

vṛttaṃ gopucchavanmūlamadhyayoḥ kṛtakarṇikam ||

cūrṇachāgalagavyamāhiṣapalasnehena samplāvitam |

pātre sthāpitamāyase kṣititale māsaṃ nidhāyoddhṛtaṃ |

pālityaṃ khalatiṃ ca darpaṇanibhāṃ hantyetadabhyañjanāt ||

Its nozzle should be twelve aṅgulas long by the patient's own finger measurement,
round like a cow's tail, with rings made at its root and middle.
Submerged in powder, meat fat of goat, cow, and buffalo,
kept in an iron vessel and placed underground for a month, then taken out,
this destroys premature graying and baldness resembling a mirror through anointing.