Anandakanda 1.23.117

1.23.117

paced bhūdharayantre ca punarādāya taṃ rasam /
haṃsapādīdravairmardyaṃ taptakhalve dinatrayam //

One should cook it in a bhūdhara apparatus, take that mercury out again,
and grind it with juices of haṃsapādī in a heated mortar for three days.