Skanda Purana — Nagara Khanda, Shloka 5
विधायापरपक्षे तु स्नापयित्वा विधानतः । मंडपाद्यं च प्राक्कृत्वा स्नात्वा धौतांबरः शुचिः
vidhāyāparapakṣe tu snāpayitvā vidhānataḥ | maṃḍapādyaṃ ca prākkṛtvā snātvā dhautāṃbaraḥ śuciḥ
随后，于月之黑半（apakṣa）中，依仪则安置诸事，并如法行沐浴净礼（snāpana）；先备办曼荼罗棚亭（maṇḍapa）及诸所需；继而沐浴，着洗净之衣，安住清净。
Bhartṛyajña (contextual continuation)
Scene: A ritual pavilion is erected; the performer bathes at a sacred waterbody, then returns in clean white garments, ready for the offering and worship.
FAQs
Purification is not only inner intent but also outer discipline—timing, cleanliness, and careful preparation.
The broader section is a tīrtha-māhātmya, but this verse focuses on ritual preparation rather than naming the site.
Perform the rite in the dark fortnight, prepare a pavilion, bathe properly, and wear clean washed clothes while maintaining purity.