no soap

Raymond ChandlerのThe Big Sleep を読んでいます。
I couldn't do it. I shifted the gun to my left hand and leaned down to scoop up a handful of gravel. I tossed it against the screen of the window. It was a feeble effort. Very little of it reached the glass above the screen, but the loose rattle of that little was like a dam bursting.
I ran back to the car and got on the running board behind it. The house had already gone dark. That was all. I dropped quietly on the running board and waited. No soap. Canino was too cagey.
俗語らしい表現の "No soap" を調べます。
・Oxford English Dictionary: Used to convey that there is no chance of something happening or occurring.: They needed a writer with some enthusiasm. No soap.
由来が気になります。長いので引用しませんが、World Wide Wordsに長々しい説明があり、The Big Sleepからの上記場面も引用されていましたが、第一次世界大戦時に兵士への石鹸の供給も滞っていた頃に発生した表現だろうと書かれていました。