Zafacón is a fun, regional word for "trash can," used primarily in Puerto Rico and the Dominican Republic. It's a great example of how Spanish varies by country.
In this classic salsa track, Héctor Lavoe uses the word to deliver a powerful diss. He sings "al zafacón yo te eché" (I threw you in the trash can), brutally dismissing a former lover as something worthless and disposable, just like yesterday's news.
Héctor Lavoe has one of the cleverest ways to describe a love that's over: "Tu amor es un periódico de ayer" (Your love is yesterday's newspaper). It’s a perfect metaphor! He says their love was a huge story when it started, a "titular que alcanzó pagina entera" (headline that took up a whole page). Everyone was talking about it. But just like a newspaper, by the afternoon it was "materia olvidada" (a forgotten matter). Now, nobody wants to read it.
He really commits to the idea, asking over and over, "¿Y para qué leer, un periódico de ayer?" (And why read yesterday's newspaper?). He gets more and more direct as the song goes on, telling his ex-lover that he threw her in the trash can and that she has an "alma de papel" (a soul of paper). It's a classic salsa song where the singer uses a simple, brilliant idea to say something we've all felt: this relationship is old news, and it's time to turn the page.