Is there an English idiom/expression that can be understood both as meaning "water under the bridge" / "yesterday's news" and as a pun regarding cocaine/drugs?
In German, there is "Schnee von gestern" (lit. "yesterday's snow") with "Schnee" also being a colloquial term for cocaine.
I'm not sure if "but that's all blown away" (referencing "blow" for cocaine) would do the trick.
In a German mag, I once read an interview with Sarah Jessica Parker where she allegedly made such a pun, and I always thought since the pun only works with the German idiom, the author must've made that part up (if not the whole interview).