cut to the bone
To make (something) the least or smallest possible amount; reduce severely; leave out everything extra or unnecessary from.
Father cut Jane's allowance to the bone for disobeying him.
When father lost his job, our living expenses had to be cut to the bone.
to the bone
Thoroughly, entirely, to the core, through all layers.
I am dreadfully tired; I've worked my fingers to the bone.
work one's fingers to the bone
To work very hard.
"I have to work my fingers to the bone for a measly pittance of a salary," Fred complained.