Michael A. Terrell wrote:

snip

I use 'Mailwasher' to bounce the garbage as undeliverable. If they
are expecting to do business with their email address, the more bounced
mail, the better to plug their inbox and prevent real customers from
contacting them.

Please don't bounce spam; this can contribute to backscatter attacks
wherein the bounced messages are returned to forged envelope sender
addresses, creating DoS floods and more spam.

Michael