sift something through something
to make something pass through something such as a sieve. she sifted the powdered sugar through a strainer. Please sift the soil through this screen and watch for bits of pottery.
sift through something
to examine all parts of something. The fire inspector sifted through the rubble, looking for clues to the start of the fire. We sifted through all the papers in the old trunk, but we did not find what we were looking for.