HUESO Y PELLEJO Literally bone and skin. To be very old, just bones and skin. From a tale written by the spanish writer Ciro Alegría, where a lady had two dogs with those names and as a burgler hided under her bed she claimed I 'm just hueso y pellejo. The dogs then came and ate the man. Some synonyms, words or similar expressions can be bones and skin
Used in US as well
"She became bone and skin. Se volvió hueso y pellejo."