Srimad Bhagavatam Canto 08, Chapter 16, Text 26

SB 8.16.26

sinivalyam mrdalipya
 snayat kroda-vidirnaya
yadi labhyeta vai srotasy
 etam mantram udirayet
 
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
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.
Srimad Bhagavatam Canto 08, Chapter 16, Text 25
Srimad Bhagavatam Canto 08, Chapter 16, Text 27