To winnow

[André Vasconcelos]

winnow

1. 
   
2. 2.

   remove (people or things) from a group until only the best ones are left.

   "guidelines that would help winnow out those not fit to be soldiers"

https://www.nytimes.com/2017/03/29/...ideos.html?_r=0 

quote:

Of the 400,000 web addresses JPMorgan’s ads showed up on in a recent 30-day period, said Ms. Lemkau, only 12,000, or 3 percent, led to activity beyond an impression. An intern then manually clicked on each of those addresses to ensure that the websites were ones the company wanted to advertise on. About 7,000 of them were not, winnowing the group to 5,000.