Question

Who gets the remnants of homa/sacrifice/puja?

Answer

Rudra (Shiva) is said to preside over sacrificial remnants, which is known as Ritual Remnant - Ucchiṣṭa (उच्छिष्ट) or śeṣa, or vāstu; and thus, as such he's the one who "metaphysically" takes/gets the remnants of sacrifice.

Some scriptural references

1. Śrīmad-Bhāgavatam MahāPurāṇa:

ŚB 4.7.56

रुद्रं च स्वेन भागेन ह्युपाधावत्समाहित: ।
कर्मणोदवसानेन सोमपानितरानपि ।
उदवस्य सहर्त्विग्भि: सस्‍नाववभृथं तत: ॥ ५६ ॥

With concentrated mind, he waited upon Rudra, by offering the share due to him (viz. the remnants of the sacrifice). By performing the concluding rite called udavasānena, he offered oblations to gods who were eligible to drink Soma and eligible to others. Thus after completely performing the sacrifice, he (Dakṣa), along with the priests (participants in the sacrifice), performed the sacred ablution called avabhṛtha.

English Translation by Motilal Banarsidass Publication

2. Śatapatha Brāhmaṇa

A more concluding and exact reference is found in Śatapathabrāhmaṇa (शतपथब्राह्मण).

The basic premise of the story being - Rudra was left behind on the sacrificial site (vāstu) by the other gods who – by means of sacrifice – ascended to heaven. Rudra went after them, and threatened to destroy the gods, and hence, gods decreed thus -

Kanda I, adhyaya 7, brahmana 3, Verse 3 to 7.

तद् वा अग्नय इति क्रियते | अग्निर् वै स देवस् तस्यै तानि नामानि शर्व इति यथा
प्राच्या आचक्षते भव इति यथा बाहीकाः पशूनाम् पती रुद्रो ऽग्निर् इति तान्य् अस्या
शान्तान्य् एवेतराणि नामान्य् अग्निर् इत्य् एव शान्ततमं तस्माद् अग्नय इति क्रियते स्विष्टकृट इति |७|

  1. The Adhvaryu accordingly sprinkled the sacrificial dishes in proper succession, and replenished them for the sake of one (additional) portion, and again rendered them fit for use, and cut off one portion for each. This then is the reason why he (Rudra) is called Vāstavya, for a remainder (vāstu) is that part of the sacrifice which (is left) after the oblations have been made: hence, if sacrificial food is offered to any deity, the Sviṣṭakṛt (Agni, 'the maker of good offering') is afterwards invariably offered a share of it; because the gods invariably gave him a share after themselves.

Translated by Julius Eggeling

And, further,

3. Taittirīya Brāhmaṇa

Taittirīya Brāhmaṇa 1.7.8.5 (तैत्तिरीयब्राह्मण)

उच्छेषणभागो वै रुद्रः | भागधेयेनैव रुद्रं निरवदयते ॥ १.७.८.५ ॥

Rudra’s share is the remnant (i.e. Ucchiṣṭa). It is said that Rudra indeed gives the share.

And finally, since Rudra is the owner of remnants, one has to offer him first, and then only such offerings become Nirmālya (literally dirtless, Pure). Thereafter the officiating priest is allowed to take away the remnants and distribute, further distribute them as prasadam, if any.

4. Skanda MahāPurāṇa

Chapter 38, Section 2 - Puruṣottama-kṣetra-māhātmya, Book 2 - Vaiṣṇava-khaṇḍa, Skanda Purāṇa (स्कन्दपुराण)

भक्त्या लोभात्कौतुकाद्वा क्षुधासंशमनेन वा । आकंठभक्षितं तद्धि पुनाति सकलांहसः ॥ ९ ॥

  1. Whether due to devotion, or covetousness or out of curiosity or as a means to satisfy hunger, if the Nirmālya is eaten to the full, it dispels all the sins

.....

यज्ञशेषं गृहस्थानां भोक्तव्यमिति शास्त्रतः । देवोच्छिष्टं न जग्राह अन्यपाकाभिशंकया ॥ ५७ ॥

  1. Since there is the injunction in the scriptural texts that the remnants of Yajña should be partaken of by householders, he did not take the remnants of the offering unto the Lord suspecting that it must have been cooked by another (inferior person).

To conclude -

The remnants of a sacrifice are presided over, and consumed (metaphysically) by Rudra. Having offered them to Rudra, the physical remains become Nirmālya, and fit to be partaken by the presiding priest of the sacrifice.

Note: “The question: Who gets the remnants of homa/sacrifice/puja?” is licensed by Stack Exchange Inc (https://hinduism.stackexchange.com/); user contributions licensed under CC BY-SA.