You might try my office trick: I have to tape a piece of paper to any pile of stuff that doesn't fit in the trash can with the word, "basura", printed in large letters and in red preferably. Otherwise, that stack of cardboard boxes and old magazines would become permanent fixtures in our file room.

But, then again, your sanitary engineers might think you were being cute...

We have a special collection twice a year for deep freezers and things like garbage cans.

Having experienced your dilemna, I will pass on my solution: Spray paint.

Use it to write your message to the garbagemen. They'll get the point, and your neighbors will get an early morning laugh. Heh.