Kaushitakagrihyasutra 2.8.7

2.8.7

tadapyetat yajñopavītaṃ daṇḍaṃ ca mekhalāmajinaṃ tathā \ juhuyādapsu vrate pūrṇe vāruṇyarcā rasena vā \7\

This also has been said: “The sacred thread, the staff, the girdle, and likewise the skin / he should cast into water when the vow is complete, with a verse addressed to Varuṇa or with ‘Rasa’.”