I'm not OP but I do something similar, which I can describe. I don't whitelist addresses, I have a domain with a catchall account. So I make up addresses as needed. When I want them to die, I add them to a ruleset on the server that punts them into the bit bucket.
So far it has been really great. Easy, effective.
Edit: Like the other reply you got, I use FastMail for this service.