Srimad-Bhagavatam: Canto 8 - Chapter 1 - Verse 26
Sanskrit:
सिनीवाल्यां मृदालिप्य स्नायात् क्रोडविदीर्णया ।यदि लभ्येत वै स्रोतस्येतं मन्त्रमुदीरयेत् ॥ २६ ॥
ITRANS:
sinīvālyāṁ mṛdālipyasnāyāt kroḍa-vidīrṇayāyadi labhyeta vai srotasyetaṁ mantram udīrayet
Translation:
If dirt dug up by a boar is available, on the day of the dark moon one should smear this dirt on his body and then bathe in a flowing river. While bathing, one should chant the following mantra.