Mbh 13.90.2c

The offerings made at Sraddhas if presented to a Brahmana who sells Soma, become converted into human ordure; if presented to a Brahmana who is engaged in the practice of Medicine, they become converted into pus and blood; if presented to one who lives by setting up a deity, they fail to produce any fruit; if presented to one who lives upon the interest of loans they lead to infamy; if presented to one who is engaged in trade, they become productive of no fruits either here or hereafter. If presented to a Brahmana who is born of a widowed mother (by a second husband), they become as fruitless as libations poured on ashes[407]. They who present the Havya and Kavya (offered at Sraddhas) unto such Brahmanas as are divested of the duties ordained for them and of those rules of good conduct that persons of their order should observe, find such presents productive of no merits hereafter. That man of little intelligence who makes gifts of such articles unto such men knowing their dispositions, obliges, by such conduct, his Pitris to eat human ordure in the next world. Thou shouldst know that these wretches among Brahmanas deserve to be excluded from the line. Those Brahmanas also of little energy who are engaged in instructing Sudras are of the same class. A Brahmana that is blind stains sixty individual of the line; one that is destitute of virile power a hundred; while one that is afflicted with white leprosy stains as many as he looks upon, O king. Whatever offerings made at Sraddhas are eaten by one with his head wrapped round with a cloth, whatever is eaten by one with face southwards, and whatever is eaten with shoes or sandals on all goes to gratify the Asuras. Whatever, again, is given with malice, and whatever is given without reverence, have been ordained by Brahmana himself as the portion of the prince of Asuras (viz., Vali). Dogs, and such Brahmanas as are polluters of lines, should not be allowed to cast their eyes upon the offerings made at Sraddhas.