Aśauca-vidhi (Rules of Impurity) within Śrāddha-kalpa — Chapter on Testing/Selecting Brahmanas and Honoring the Atithi
अन्यच्च दधिसर्पिर्भ्यां शिष्टं पुत्राय नान्यथा / अवशेषं तु दातव्यमन्नाद्यं तु विशेषतः
anyacca dadhisarpirbhyāṃ śiṣṭaṃ putrāya nānyathā / avaśeṣaṃ tu dātavyamannādyaṃ tu viśeṣataḥ
Whatever remains of curd (dadhi) and ghee (ghṛta) should be given only to the son, not otherwise. But other leftovers should be given in charity—especially food and edibles.