I was thinking about the phrase ‘The pot calling the kettle black’. It comes from a time where cooking was done over open fires and cookware would become visibly ashy. (Fun fact: It first appears and was perhaps coined by Cervantes in Don Quixote!)
What are some other idioms that have lost their literal connection to time? What would be a good modern replacement?
They don’t need to have been used routinely, just knowledge of their use had to be common. In the same way that “shooting yourself in the foot” makes sense even to people who have never used a gun. It was enough to know what “hoist” and “petard” meant to piece together the intent of the phrase. Then once the phrase itself became common the specific knowledge was no longer necessary.