Fig.: to reduce something as much as possible. To reduce something to next to nothing

The economy was in a severe downturn and both industry and commerce had to cut costs to the bone in order to survive

L'economia era in un momento molto difficile e sia l'industria che il commercio hanno dovuto ridurre i costi all'osso per poter sopravvivere

These are hard times: although we've cut our expenses to the bone, we are still barely breaking even

È un momentaccio: abbiamo dovuto ridurre le spese all'osso per andare a malapena in pari

Reduced to its bare bones, the political scientist's theory was that anyone who flies the flag against the Mafia, in Sicily becomes an almighty that can't be touched

Ridotta all'osso, la tesi del Famoso politologo sosteneva che chi sventola la bandiera della lotta alla Mafia diventa, in Sicilia, un potente intoccabile

This self-explaining phrase dates back to the 1400s and means that everything unessential has been cut away and only the core (bone) remains