SB 8.11.40

na śuṣkeṇa na cārdreṇa
 jahāra namuceḥ śiraḥ
taṁ tuṣṭuvur muni-gaṇā
 mālyaiś cāvākiran vibhum
Synonyms: 
na — neither; śuṣkeṇa — by dry means; na — nor; ca — also; ārdreṇa — by a moist weapon; jahāra — he separated; namuceḥ — of Namuci; śiraḥ — the head; tam — him (Indra); tuṣṭuvuḥ — satisfied; muni-gaṇāḥ — all the sages; mālyaiḥ — with flower garlands; ca — also; avākiran — covered; vibhum — that great personality.
Translation: 
Thus Indra, King of heaven, severed Namuci’s head with a weapon of foam, which was neither dry nor moist. Then all the sages satisfied Indra, the exalted personality, by showering flowers and garlands upon him, almost covering him.
Purport: 

In this regard, the śruti-mantras say, apāṁ phenena namuceḥ śira indro ’dārayat: Indra killed Namuci with watery foam, which is neither moist nor dry.