According to the submissions on wowhead the drop chance for Schnottz Infantryman - NPC - World of Warcraft is about 50% and drops 1-3 embersilk.
They walk in packs of 9. That means with good luck you can get 27 embersilk per pack or with horrible luck you could get very few.
In addition to this you also kill Schnottz Elite Infantryman - NPC - World of Warcraft which has about a 50% chance to drop 1-6 embersilk.
This method may have been hot-fixed but if it hasn't then this a viable method and the OP deserves credit.