Green’s Dictionary of Slang

clean adv.

[SE clean, completely, entirely]

1. honestly.

[UK]Skelton Dyvers Balettys and Dyties Solacyous ii line 41: Play fayre-play, madame, and loke ye play clene, Or ells with gret shame your game wylbe sene.
[US]‘Ned Buntline’ G’hals of N.Y. 143: For my part, whenever I do a thing, I always like to do it clean!
[US](con. early 1950s) J. Ellroy L.A. Confidential 25: You’ve probably got documentation worked around to let you off clean and crucify me.

2. (US) in profit.

[US]C.L. Cullen Tales of the Ex-Tanks 21: How’d I make out? Oh, only about $50 to $100 a day, clean, that’s all.

SE in slang uses

In phrases

clean around the bend (adj.) [around the bend adj. + pun on advertising slogan for the lavatory cleaner Harpic]

utterly insane.

[US]M.A. Margetson ‘Computer Games’ [poem] 🌐 Some times they drive you crazy / Make your head feel hazy / Send you clean around the bend.
clean broke (adj.) [broke adj.1 ]

absolutely penniless.

[UK]Era 18 Nov. 5/4: People told him that he would soon be ‘clean broke’.
[Scot]Dundee Courier 7 Jan. 3/5: A worthy widow [...] told me one of our bad years that ‘she would have been clean broke if it had not been for the strawberries.
[UK]Derby Dly Teleg. 29 Sept. 2/8: Hill said he had been clean broke and willingly accepted £25 for his blood.
[US]J. London Burning Daylight Pt II Ch XIX 🌐 But suppose your prayer should be answered and I’d go clean broke and have to work for day’s wages?
[US]W. Winchell On Broadway 18 Feb. [synd. col.] There’s the lad who was clean broke recently, who didn’t have enough coin for a gallon of gas.
[UK]Essex Newsman 12 Dec. 3/7: Most of us were clean broke and had no prospect even of gtting enough money to buy food.
V. Lindsay ‘When Gassy Thompson Struck it Rich’ [poem] in Congo and Other Poems 🌐 The Swede had twenty cents, all right. / But Gassy Thompson was clean broke.