Ah, subtitling The Flintstones, The Simpsons and other comedies. Great fun, but an awful lot of idioms to deal with…
For example, in an episode I did this week, Fred tells Wilma that he’s not joining the army but helping out with the scouts (hence the uniform he’s wearing). Wilma says: “I thought for a minute the Army had gotten to the bottom of the barrel.” She’s actually playing with the well-know expression “to scrape the bottom of the barrel”. This expression (very visual but not to be taken literally) denotes a situation in which someone has exhausted their resources so much that they have got to the bottom of an imaginary barrel.
There isn’t a similar common expression in French to express the idea that after going through all your options, you’re left with the dregs and have to make do with what you’ve got. So I went for an equivalence with “J’ai pensé un moment que l’armée devait vraiment être désespérée” (I thought for a while that the army must really be desperate).
It’s a shame to not be able to offer an idiom that is as well-known as this one is in English, but at least the meaning is conveyed and it’s still a humourous way of expressing her surprise at the army accepting Fred in their ranks.