Abstract: A system for handling email messages comprising: at an originating email server: obtaining a token from a finite pool of valid tokens associated with a sender of an email message that is to be sent to an addressee; incorporating the token into the email message; sending the email message towards its addressee; at a receiving system: inspecting an incoming email message for the presence of a token and establishing the validity of the token; and if a valid token is present, delivering the message to the addressee, and otherwise rejecting the message; or delivering the message to a primary mail box of the addressee if a valid token is present and otherwise delivering the message to a secondary mail box of the addressee; at an addressee's system: acting, responsive to an event indicative that the message is objectionable, to cause the token to be removed from the pool of valid tokens.