1
general::
Phrase(s): blow the lid off (something)
Sl. to expose something to public view. • The police inspector blew the lid off the work of the gang of thugs. • The investigation blew the lid off the scandal.
McGrawhill's American Idioms And Phrasal Verbs
2
general::
Also, blow wide open. Expose, especially a scandal or illegal activity. For example, The newspaper's investigation blew the lid off the governor's awarding state contracts to his friends. [First half of 1900s]
American Heritage Idioms