Drain: to draw off (liquid) gradually or completely
vs.
Decant: to draw off (a liquid) without disturbing the sediment or the lower liquid layers
Even if you are using jarred olives for some reason, you pretty much want the "sediment" (aka, THE OLIVES)
Had no choice but to pay $40 for a taxi burrito because I couldn't figure out how to decant olives
Google Image search led me to FB:
things are not going well in the twin cities my friends