Anandakanda 2.1.244

2.1.244

nalikāsampuṭaṃ baddhvā śoṣayed ātape khare /
grāhyaṃ pātālayantreṇa sattvaṃ dhmāte puṭe'tha vā //

Having bound the tube crucible enclosure, one should dry it in harsh sunlight;
the essence should be gathered by means of the pātāla apparatus, or when the enclosure is blasted.