Shiva Purana
अभ्यर्च्य गन्धपुष्पाद्यैर्धूपदीपौ प्रदर्श्य च॥ संरक्षास्त्रेण तं शंखं वर्मणाथावगुण्ठयेत् ॥ २१ ॥
He shall worship it with scents and flowers and show lights and incense. He shall then cover up the conch with Astra and Varma mantras.
english translation
abhyarcya gandhapuSpAdyairdhUpadIpau pradarzya ca॥ saMrakSAstreNa taM zaMkhaM varmaNAthAvaguNThayet ॥ 21 ॥
hk transliteration by Sanscript