Anandakanda 1.4.339

1.4.339

kṣāradvayaṃ pūrvarase kṣiptvā sthāpyaṃ tryahaṃ khare /
ātape tadvastrapūtaṃ lohapātre dravaṃ pacet //

and having thrown the two alkalis into the former liquid, it should be kept for three days in the sharp
sunshine. One should cook that liquid, filtered through a cloth, in an iron vessel.