What it means: To reveal a secret or an honest opinion. Where it comes from: In Ancient Greece, they believed that using beans was one of the fairest ways to vote for someone who was attempting to join a party or an organisation. So, if you agreed with the candidate, you would place a white bean into their jar and if you disapproved, you would place a black bean. The bean represented your vote. But unfortunately, accidents happen and someone would quite literally spill the beans about the candidate. By knocking over the jar, everyone could see how many votes they had and which favour people were voting for.
