Free from blame or fault.
“Ye are clean, but not all.” - John xiii. 10.
BILL. To show a clean bill of health. (See page 135, col. 1, Bill Of Health.) BREAST. To make a clean breast or Make a clean breast of it. To make a full and unreserved confession. HANDS. To have clean hands. To be quite clear of some stated evil. Hence “clean-handed.”
HEART. To have a clean heart. A righteous spirit.
“Create in me a clean heart, and renew a right spirit within me.” - Psalm li. 10.
HEELS. To show a clean pair of heels. To make one's escape, to run away. Here “clean” means free from obstruction.
“The Maroons were runaway slaves who had ... shown their tyrants a clean pair of heels” —Sala.
LIFE. To live a clean life. Blameless and undefiled.
TONGUE. A clean tongue. Not abusive, not profane, not foul.
Clean, used adverbially, means entirely, wholly; as, “you have grown clean out of knowledge,” i.e. wholly beyond recognition.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894
More on Clean from Fact Monster: