When you defeat & loot a Drow Warrior or Assassin, as in MM, do you get a permanent poison sword?

@mackenzie884D&D ?: When you defeat & loot a Drow Warrior or Assassin, as in MM, do you get a permanent poison sword? nope, poison dries out

— Mike Mearls (@mikemearls) February 25, 2016

@RobertPascuttin @JeremyECrawfordPoison on drow elite warrior sword has no duration in stat block. Does it expire after 1 hit or stays longer? lasts multiple hits

— Mike Mearls (@mikemearls) April 25, 2016