Ashtangasamgraha 39.8

39.8

Thus [he prays].
Then on the next day, if he sees no portent or unnatural omen there, when the sun has risen to the height of a yoke, having caused the brahmins to recite auspicious mantras, he should fell that tree toward the east or toward the north.
And likewise pāribhadra, palāśa, aśvakarṇa, rājavṛkṣa, mahāvṛkṣa, vṛkṣaka, indravṛkṣa, āsphota, saptacchada, naktamāla, tilvaka, kadalī, bibhītaka, aśvamāraka, pūtīka, citraka, arka, kākajaṅghā, apāmārga, and agnimantha; and barley collected in spring with its awns and stalks; and four [kinds of] kośātakī, along with their roots, fruits, leaves, and branches—having cut them into pieces, placed them upon stone slabs not excessively dried, stacked them separately in a windless place, and having thrown limestone into the stack of muṣkaka, he should ignite them with sesame stalks.
And when burned and the fire is extinguished, having separated the ashes of the limestone, he should stir the remaining one droṇa of all the ashes, with an excess of muṣkaka, into one thousand palas of water and one thousand palas of urine of cows and other [animals], and filter it through a large cloth.
When it has become clear, red, sharp, and slimy, then taking that caustic filtrate, he should discard the ash.
Then he should cook it according to the method for cooking unctuous substances.
And while it is being cooked, he should heat those lime-ash stones, along with the white layer of oyster shells, conch columella, and iron vessel red-hot in the fire, quench them in a measure of just one kuḍava of that clear caustic, grind them extremely smooth with that very [liquid], and add them as an additive.
Then, stirring thoroughly with a ladle, he should cook it until it rises with steamy bubbles and, through thickness, adheres to the ladle; then he should take it down and place it well-concealed in an iron jar inside a heap of barley.
This is the moderate caustic.
Or an application with honey, oil, and ghee is best on an ulcer;
or with lākṣā, drākṣā, linseed, and honey, [or] with honey, śaileya, and tārkṣyaja.