Rasadhyaya 92

92

sūte'ṣṭādaśasaṃskārās tatrādyaḥ pāṭasāraṇaḥ
dvitīyo mardano nāma tṛtīyaḥ śodhano mataḥ //

There are eighteen alchemical processings for mercury: among them, the first is cloth-filtration; / the second is called grinding; the third is considered purification;