What to do with leftover citrus

Citrus is the one ingredient almost every cocktail recipe insists has to be fresh, which means it's also the ingredient most likely to sit around going soft after a single recipe only needed half a lime. Rather than let the rest dry out, it's usually worth building a second drink around whatever's left — fresh citrus juice keeps for a day or two at most, so this is a use-it-soon list, not a use-it-eventually one.

Grouped below by which juice each recipe actually needs, so you can jump straight to whichever fruit you're trying to get through.