Anandakanda 2.4.17

2.4.17

vārān dvādaśataḥ śuddhaṃ lepāttāpācca secanāt /
khaṭikāṃ lavaṇaṃ takrairāranālaiśca peṣayet //

It is purified after twelve times through smearing, heating, and sprinkling. / One should grind chalk and salt with buttermilk and fermented sour gruel;