I just got off the telephone with an executive assistant and we were discussing ways she is trying to cut down on the volume of incoming mail to her CEO. One area she focused on were publications, magazines, advertising, non-pertinent newsletters or e-zines, marketing information, etc.
The prior executive assistants told her to just delete those items when they came in. The problem with that is those emails keep coming back. You need to actually unsubscribe your executive from them. It may take you a few extra steps but will save you a great deal of time in the long run.