Shiva Purana
आग्नेयमुच्यते भस्म दग्धगोमयसंभवम् । तदापि द्र व्यमित्युक्तं त्रिपुंड्रस्य महामुने ६ ।
When dry cow-dung is reduced to ashes it is called Agneya (fiery). O great sage, for the sake of Tripuṇḍra this ash can be used.
english translation
Agneyamucyate bhasma dagdhagomayasaMbhavam । tadApi dra vyamityuktaM tripuMDrasya mahAmune 6 ।
hk transliteration by Sanscript