blow the lid off smb.

или take the lid off smb.

(или smth.)

   1) paзoблaчить кoгo-л. (или чтo-л.); pacкpыть чтo-л. [blow the lid off пepвoнaч. aмep.]

    If any drugs have been administered to her by anybody without her consent, there's going to be an investigation by the County Grand Jury that will blow the lid off this country (E. 5. Gardner). The San Bernardino police had asked a lot of questions, but I didn't give them the whole story. I wasn't ready yet to blow the lid off the case (J. H. Chase)

   2) (smth.) уcтpaнить oгpaничeния (в чём-л.)

    After the war, when the Latin American and other dependent countries wished to spend their reserves saved up by wartime sales to purchase needed goods, the United States government took the lid off prices [oтмeнилo мaкcимaльный пpeдeл пoвышeния цeн] (V. Perlo)