Green’s Dictionary of Slang

cleanskin n.

also clearskin
[SE cleanskin/clearskin, an unbranded cow]

1. a person without a criminal record, also in fig. sense, one who lacks previous (criminal) associations (see cite 1999) or moral failings (see cite 1925).

[[Aus]Truth (Sydney) 1 July 5/5: That night we started out to get some clean skins (unbranded cattle)].
[Aus]Truth (Brisbane) 10 Feb. 13/4: In the parlance of legal colloquialism the defendant was a cleanskin in that he had not previously contributed his name to be handed down to posterity in police court annals.
[Aus]Smith’s Wkly (Sydney) 19 Dec. 3/2: Yer can walk up to papa Peter, and he’ll say: ‘Who goes there!’ and yer’ll answer, ‘Clean skin,’ and ’e’ll answer, ‘Pass cleanskin, all’s well.’.
[Aus]Sun (Sydney) 10 Jan. 11/1: Your request would be all right if you were a cleanskin [...] but you have had four convictions for dishonesty, and a couple down at the Children’s Court.
[Aus]Baker Aus. Lang. 141: A man who has had no convictions recorded against him is a cleanskin.
[Aus]S.J. Baker in Sun. Herald (Sydney) 8 June 9/2: There’s [...] the ‘cleanskin,’ ‘squarehead’ or ‘squarey,’ the new crook who has had no previous convictions.
[NZ]G. Newbold Big Huey 246: cleanskin (n) Person without a criminal record. From Australian pastoral slang for unbranded cattle, a word in use there in the 1880s.
[Aus]R.G. Barrett Real Thing 54: He might be from interstate. He might even be a clean-skin.
[Aus]Tupper & Wortley Aus. Prison Sl. Gloss. 🌐 Clean skin. A first offender or more generally any person who has not been in trouble with the law.
[Aus]P. Temple Black Tide (2012) [ebook] Canetti was the only cleanskin we had.
[UK]Observer 17 July 15: The view was that the group of ‘clean skins’ with no previous known links to terrorists, would have needed a controller.
[Aus]D. Whish-Wilson Zero at the Bone [ebook] [N]one of Gary’s private school mates would be here tonight, [...] but that didn’t mean they were cleanskins. Life in the better suburbs was boring, so middle-class boys needed more excitement.
[UK]T. Thorne (ed.) ‘Drill Slang Glossary’ at Forensic Linguistic Databank 🌐 Clean skin – individual without a criminal record, unknown to police.

2. an honest person, esp. in politics.

Dly Standard (Brisbane) 3 July 1/8: An expression of a desire to start as a cleanskin and turn over a new leaf was alleged [...] to have been the reply of a man to a detective who charged him with stealing.
[Aus]West Australian (Perth) 8 Apr. 25/1: Mr. Walker said that he was standing as a Labour independent, and he claimed that he was a ‘Labour cleanskin’.
[Aus]Baker Popular Dict. Aus. Sl. 18: Cleanskin, a person of integrity, esp. in a political sense.
I. Yusuf 26 June 🌐 So when it comes to racism and xenophobia, both Jewish and Muslim leaders aren’t exactly cleanskins.
[Aus]S. Maloney Sucked In 47: Thorsen was a cleanskin, untarnished by our period in government.
[UK]Daily Mail 4 July 🌐 Gove was well known to be an ideological ninja [...] but when it came to the top job he was an avowed cleanskin.
[Aus]C. Hammer Opal Country 299: She needs to demonstrate to Phelan that she’s a cleanskin, that she’s acting in good faith.
Twitter 26 Feb. 🌐 But Zelenskiy is a clean-skin. He's a satirist funnyman who until v. recently made dick jokes for a living.

3. unbranded wine, the label of which shows only the variety of grape, the year of bottling, the alcoholic content, etc. but no manufacturer/vineyard.

[Aus]J.J. DeCeglie Drawing Dead [ebook] I grabbed five white wine clean-skins that were going for four bucks a bottle.