winnow out
Verb
Meaning
dismiss from consideration or a contest
Source: WordNetSynonyms
Examples
Guerrilla marketing requires you to comprehend every facet of marketing, experiment with many of them, winnow out the losers, double up on the winners, and then use the marketing tactics that prove themselves to you in the battleground of real life.
John was ruled out as a possible suspect because he had a strong alibi
This possibility can be eliminated from our consideration