Mahabharata 13.129.38

एष तेषां विशुद्धानां फेनपानां तपोधनेधर्मचर्याकृतो मार्गो वालखिल्यगणे शृणु

eṣa teṣāṃ viśuddhānāṃ phenapānāṃ tapodhanedharmacaryākṛto mārgo vālakhilyagaṇe śṛṇu

Our plain-language meaning of this verse is waiting for scholar review.