Question

Clean as a Whistle completely free from dirt; perfectly neat

Accepted Answer

The science lab is as clean as a whistle. In one of his poems in the late 1700s, Robert Burns, a great Scottish poet, used a similar phrase, "as toom's a whissle" ("toom" meant "empty" then). The idea is that you can get the best, clearest, purest sound out of a whistle or any other wind instrument if you keep the reed (the part that makes the sound when you blow into it) completely free of dust and dirt. A similar expression is "clean as a hound's tooth."

Idiom	Clean as a Whistle
Example	The science lab is as clean as a whistle.
Meaning	completely free from dirt; perfectly neat
Origin	In one of his poems in the late 1700s, Robert Burns, a great Scottish poet, used a similar phrase, "as toom's a whissle" ("toom" meant "empty" then). The idea is that you can get the best, clearest, purest sound out of a whistle or any other wind instrument if you keep the reed (the part that makes the sound when you blow into it) completely free of dust and dirt. A similar expression is "clean as a hound's tooth."

Whistle Clean Completely Free Similar Sound Science Lab