What is a recycled spam trap?

A recycled spam trap began as a real inbox that was later abandoned. Providers first deactivate the address and issue hard bounces such as a 550 User Unknown for a cooling period that may span several months. After that period the address is quietly converted into a trap.

If you keep sending to these addresses it shows weak sunsetting practices and failure to honor hard bounces.

It is like continuing to deliver cargo to an abandoned warehouse long after the doors have been chained shut. Eventually the harbor authority marks it as suspicious.