clean as a whistle

Idioms  

1. Completely, entirely, thoroughly, as in He chopped off the branch, clean as a whistle. The allusion in this simile is unclear. It may have been a replacement for the 18th-century clear as a whistle, which alluded to the pure, clean sound of a whistle (it has few overtones). However, it was adopted to describe something thoroughly done. [Early 1800s]

---

Example Sentences

After escaping a pair of masked assailants, he brings the police around; the sauna, you will have guessed, is clean as a whistle.

From Los Angeles Times

When I come to, I’m in the recovery room, head still cloudy, soul unsettled but clean as a whistle.

From New York Times

"He’s got a crack in his lower leg that they fixed and operated on. It went clean as a whistle, really good. It was as good as it could humanly be as far as the prognosis of things," Fisher said, via Yahoo Sports.

From Fox News

I searched online how best to get that area clean as a whistle with no viable results.

From Slate

“Clean as a whistle, sharp as a tack.”

From Washington Post