Śatapatha Brāhmaṇa ("of a hundred paths") 1.8.2.1

1.8.2.1

te vā ete ulmuke udūhanti | anuyājebhyo yātayāmeva vā etadagnirbhavati devebhyo hi yajñamūhivānbhavatyayātayāmnyanuyājāṃstanavāmahā iti tasmādvā ete ulmuke udūhanti

They now remove two burning samidhs (from the Âhavanîya fire). That fire, indeed, is now worn out, (and therefore useless) for the after-offerings, since it has been carrying the sacrifice to the gods: 'Let us perform the after-offerings in such (fire) as is not out-worn!' thus they think, and for this reason they remove those two burning samidhs (from the fire).