Srimad-Bhagavatam: Canto 11 - Chapter 1 - Verse 10
Sanskrit:
पूर्वं स्नानं प्रकुर्वीत धौतदन्तोऽङ्गशुद्धये ।उभयैरपि च स्नानं मन्त्रैर्मृद्ग्रहणादिना ॥ १० ॥
ITRANS:
pūrvaṁ snānaṁ prakurvītadhauta-danto ’ṅga-śuddhayeubhayair api ca snānaṁmantrair mṛd-grahaṇādinā
Translation:
One should first purify his body by cleansing his teeth and bathing. Then one should perform a second cleansing by smearing the body with earth and chanting both Vedic and tantric mantras.