winnowed

Winnowed is the past tense of winnow, which originally meant to separate grain from chaff by tossing it in the air and letting the wind blow away the lighter waste material.

This core sense of separation and refinement extends to figurative uses: to winnow a list or group is to reduce it by removing less desirable elements.

The applicant pool was winnowed down to three finalists.

Something winnowed has been sorted, sifted, or refined through a process of elimination.