What does “Más difícil que sacarle caldo a un riel” mean in Costa Rica?

Next to impossible.

Word for word: Harder than getting broth out of a rail.

How to say it

más di·fí·cil que sa·car·le cal·do a un riel

Try it yourself

Tap the word to hear it in a Costa Rican voice. Press and hold it to say it and get a score out of 100.