There are numerous such verses in the Smritis. Consuming Panchagavyas (the five products obtained from a cow) is considered as an effective sin-cleansing remedy for a variety of sins.
Here are a few verses from various chapters of Parashara Smriti:
28. Urine of the cow, cow-dung, milk, curd, and ghee, these five are the five articles derived from a cow. They, and water in which the
kusa grass has been dipped, — are themselves pure, and therefore
purify the sin.
- A Krichchhra-santapana consists in eating cow-dung, cow's urine, milk, curd, ghee, and water in which kusa grass has been dipped, and
likewise a fast for a single night.
Where a Brahman from ignorance follows the corpse of one who belongs
to the military caste, he becomes impure for a single night, and
purifies himself by eating the fivefold products of a cow. [These are,
milk, curd, clarified butter, cow's urine and cowdung.]
For drinking water raised from a well, into which a Chandala's pot has been dipped, purity may be restored by drinking for three nights
cow's urine in which half-ripe barley has been blended.
When a Brahman through ignorance chances to eat any food that belongs to one of the Chandala caste, he should purify himself by
living on half-ripe barley and cow's urine for ten nights
In case of association for a month or half a month, with persons belonging to the Chandala caste, purity returns by living on cow's
urine, wherewith unripe barley is mixed, during the period of half a
According to the Parashara Smriti, Vedic deities reside in each of these five products from the cow.
- The god Varuna is in the urine of the cow ; the god of sacrificial fire in the cow-dung ; the god of wind in the curd ; the
moon in the milk ; and the sun in the ghee
(Here is a related post : Why is Panchagavya considered holy in Hinduism?)
Here are more such relevant verses from Manu Smriti:
11.90. A twice-born man who has (intentionally) drunk, through delusion of mind, (the spirituous liquor called) Sura shall drink that
liquor boiling-hot; when his body has been completely scalded by that,
he is freed from his guilt;
11.91. Or he may drink cow’s urine, water, milk, clarified butter or (liquid) cowdung boiling-hot, until he dies;
11.212. (Subsisting on) the urine of cows, cowdung, milk, sour milk, clarified butter, and a decoction of Kusagrass, and fasting during one
(day and) night, (that is) called a Samtapana Krikkhra