Srimad-Bhagavatam: Canto 11 - Chapter 1 - Verse 3
Sanskrit:
केशरोमनखश्मश्रुमलानि बिभृयाद् दत: ।न धावेदप्सु मज्जेत त्रिकालं स्थण्डिलेशय: ॥ ३ ॥
ITRANS:
keśa-roma-nakha-śmaśru-malāni bibhṛyād dataḥna dhāved apsu majjetatri kālaṁ sthaṇḍile-śayaḥ
Translation:
The vānaprastha should not groom the hair on his head, body or face, should not manicure his nails, should not pass stool and urine at irregular times and should not make a special endeavor for dental hygiene. He should be content to take bath in water three times daily and should sleep on the ground.