CC Madhya 24.338

puraścaraṇa-vidhi, kṛṣṇa-prasāda-bhojana
anivedita-tyāga, vaiṣṇava-nindādi-varjana
Word for word: 
puraścaraṇa-vidhi — ritualistic ceremonies; kṛṣṇa-prasāda-bhojana — eating the remnants of food offered to the Lord; anivedita-tyāga — not touching anything not offered to the Lord; vaiṣṇava-nindā-ādi-varjana — completely avoiding blaspheming a Vaiṣṇava.
Translation: 
“Other items you should describe are the method of performing puraścaraṇa, taking kṛṣṇa-prasādam, giving up unoffered food and not blaspheming the Lord’s devotees.
Purport: 

Regarding the vaiṣṇava-nindā, see Madhya-līlā 15.261.