Mbh 12.193.2b

They are like the lacteal sustenance that is yielded by the mother's breast. People highly prize those remnants. The good, by eating them attain to Brahma. He who pounds turf to clay (for making sacrificial altars), or he who cuts grass (for making sacrificial fuel), or he who uses his nails only (and not weapons of any kind) for eating (sanctified meat), or he who always subsists on the remnants of Brahmana's dishes, or he who acts, induced by desire for reward, has not to live long in the world.[592] One who has abstained from meat (under any vow) should not take meat even if it be sanctified with mantras from the Yajurveda. One should also avoid the flesh about the vertebral column (of any animal) and the flesh of animals not slain in sacrifices.[593] Whether at one's own place or in a strange land, one should never cause one's guest to fast. Having obtained alms and other fruits of optional acts, one should offer them to one's seniors. One should offer seats to one's seniors and salute them with respect. By worshipping one's seniors, one obtains long life, fame, and prosperity. One should never behold the Sun at the moment of rising, nor should one turn one's gaze towards a naked woman that is another man's spouse. Congress with one's wife (in her season) is not sinful but it is an act that should always be done in privacy. The heart of all sacred spots and shrines is the Preceptor. The heart of all pure and cleansing things is Fire. All acts done by a good and pious person are good and laudable, including even the touching of the hair of a cow's tail. Every time one meets with another, one should make polite enquiries. The saluting of Brahmanas every morning and evening is ordained. In temples of gods, amid cows, in performing the rites of religion laid down for Brahmanas, in reading the Vedas, and in eating, the right hand should be raised.[594] The worship of Brahmanas, morning and evening, according to due rites, produces great merit.