fine-tooth comb, to go over with a

go over something with a fine-tooth comb

 and search something with a fine-tooth comb; go through something with a fine-tooth comb

Fig. to search through something very carefully. I can't find my calculus book. I went over the whole place with a fine-tooth comb. I searched this place with a fine-tooth comb and didn't find my ring.

See also: comb, go, over

McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.

fine-tooth comb, to go over with a

To search for or investigate with scrupulous care. Although combs have been known since the time of ancient Egypt, and presumably some had finer teeth than others, the term “fine-tooth comb” dates only from the first half of the nineteenth century. The transfer of combing out nits to other kinds of search or investigation took place only in the late nineteenth century.

See also: go, over

The Dictionary of Clichés by Christine Ammer Copyright © 2013 by Christine Ammer