Manava Dharmashastra 11.150

11.150

ajñānāt prāśya viṇmūtraṃ surāsaṃspṛṣṭam eva ca
punaḥ saṃskāram arhanti trayo varṇā dvijātayaḥ //

But when a Brahmana who has partaken of Soma-juice, has smelt the odour exhaled by a drinker of Sura, he becomes pure by thrice suppressing his breath in water, and eating clarified butter.