leave no stone unturned

carved in stone

Unchangeable.

cast the first stone

To act self-righteously in accusing another person, believing oneself to be blameless.

eat and leave no crumbs

Synonym of eat (“to be very good at something; to rule; to rock”).

French leave

A departure taken quietly and unnoticed, without asking for permission or informing anyone.

get blood out of a stone

To do something difficult, frustrating, or pointless.

kill two birds with one stone

To solve two problems with one single action.

leave a sour taste in one's mouth

To give one an unpleasant feeling or memory.

leave at the door

To dispense with something for now; to forget about it situationally, or omit or discard it in a given place or instance.