https://tinyurl.com/y3ra9h9q
This is an addendum to: Soma yajna depicted on Bactria silvervase with Brahman and seven R̥gveda priests and artisans at work, Indus Script hieroglyphs
Perforated pot. Mohenjo-daro ca. 2700 to 2000 BCE
शता* तृण्ण mf(आ)n. having a hundred holes Br. Kaus3.
शता* तृण्णा f. a jar or vessel having a hundred holes (शतपथ-ब्राह्मण,वैतान-सूत्र)
Satapatha Brahmana ( 12.7.2.13) śatā́tṛṇṇā́ kumbhī́ bhavati refers to such a pot.
Sentence: a śatā́tṛṇṇā́ kumbhī́ bhavati /
Sentence: b bahudhèva hí sá vyásravad átho śatónmā́no vaí yajñó yajñám evā́varunddhe sátaṃ bhavati sádevā́varunddhe cápyaṃ bhavaty annā́dyasyaivā́varuddhyai pavitráṃ bhavati punánti hy ènaṃ vā́lo bhavati pā́pmanó vyā́vṛttyai suvárṇaṁ híraṇyaṃ bhavati rūpasyaivā́ruddhyai śatámā́naṃ bhavati śatā́yur vaí púruṣaḥ śaténdriya ā́yur evèndriyáṃ vīryàm ā́tmán dhatte //
13. There is a pot (kumbhî) perforated with a hundred holes 1, for in many ways did that (Soma) flow out of (Indra); and a hundred-sized also, indeed, is the sacrifice: it is the sacrifice he thereby secures. There is a bowl (rata 2): it is the real (or good) thing (sat) he thereby secures. There is a dish (kapya) for him to secure food. There is a filter, for they cleanse him, (the Sacrificer, by this offering). There is a tail (-whisk) for turning away evil. There is gold for him to secure form (or colour); it weighs a hundred (grains), for man has a life of a hundred (years) and a hundred energies: life, and energy, vital power, he thus lays into his own self.
https://www.sacred-texts.com/hin/sbr/sbe44/sbe44066.htm
At XII, 7, 2, 13 a perforated pot (with a hundred holes) was mentioned as being used at this sacrifice. According to Kâty. Sr. p. 235 XIX, 3, 20, and Mahîdhara on Vâg. S. XIX, 37, use is made of this pot at this juncture in much the same way as is described in V, 5, 4, 27 seqq.; viz. two poles are driven into the ground north and south of the southern fire, and a bamboo stick laid thereon: on a string fastened to this stick the pot, containing a tail-whisk (for straining) and a piece of gold, is then made to hang over the fire, and the remains of the Surâ-liquor poured into it; and whilst it trickles through into the fire, the priest makes the Sacrificer pronounce the verses Vâg. S. XIX, 37-44, 52-60, addressed to the different kinds of departed ancestors.
https://www.sacred-texts.com/hin/sbr/sbe44/sbe44068.htm#12:8:1:8
The 'sura' used in perforated pots is clearly herbal extract which performs the functions of calcination, by infusing carbon into the molten metal in the fire-altar.
In some cases, calcination of a metal results in oxidation of the metal.
Examples of calcination processes include the following:
- decomposition of carbonate ores, as in the calcination of limestone to drive off carbon dioxide;
- decomposition of hydrated minerals, as in the calcination of bauxite and gypsum, to remove water of crystallization as water vapor;
- decomposition of volatile matter contained in raw petroleum coke;
- heat treatment to effect phase transformations, as in conversion of anatase to rutile or devitrification of glass materials
- removal of ammonium ions in the synthesis of zeolites.https://en.wikipedia.org/wiki/Calcination