Both of these great answers will get the client out of the EF homebase.
I also like to go to the client status page. The last line after all of the checkboxes for type of status is a blank choice which I put "mail" or "mail reject". It automatically includes date. This way the individual homebased shows a status of mail. From time to time I look at that database and sort by the status column to see the few clients that did not efile