Is there any idiomatic expression with the meaning "show all the hidden stuff"?

Which idiomatic phrase can be used to express 'showing all the hidden stuff' (it's supposed that nobody should find that out, some scandal things)?

Blow the lid off something.

"Spill the beans" or just "Spill it."

Let the cat out of the bag

Uncover the skeletons in the closet or, similarly, show where the bodies are buried.

From The Telegraph: "A married magistrate was discovered defrauding a charity she worked for after her lover of 10 years blew the whistle." More common is the noun form: whistleblower.

Do you want to describe an outsider discovering secrets or an insider revealing them? Most idioms that I can think of lean one way or the other.