表達as clean as a whistle 像口哨一樣干凈用來形容事物極其干凈或某人沒任何前科或污點。在用時，可以直接說人或物clean as a whistle。關于這個說法的由來有不少，有人覺得as clean as a whistle曾用來形容劍劃過物體時發出的清澈的聲音，也有人稱，它來自于大家吹奏蘆葦或木制哨子時所發出的清脆聲音。

例句

Ive never even been issued a speeding ticket my driving licence^{1 is clean as a whistle.}

我從來沒收到過一張超速罰單，我的車本上一分都沒扣，毫無污點。

Jen is a bit of a neat freak. She keeps her desk clean as a whistle.

珍是一個酷愛整齊的人，她的辦公桌一直打掃得極其干干凈凈。

Youve really tidied it up here its as clean as a whistle!

你真的認真地做了掃除，這里看著特別干凈！