Probably better than sending everyone a note and deleting them all is
to use LISTSERV's Renewal service:
 
Edit your LIST configuration file, adding in this line (if there is
not already a Renewal keyword in your list, or if its current
renewal date/delay is not what you want):
 
*  Renewal= sometimesoon,Delay(whatevernumberofdays)
 
where "sometimesoon" is a date, yy/mm/dd, at the first opportunity
that you wish to send out a renewal notice, and ...
 
where "whatevernumberofdays" is a number of days delay between the
time the renewal notice is sent and when the Confirmation must be
returned/received by LISTSERV by the subscriber (or his subscription
is cancelled).  The default Delay is 7 days (if you want the default,
just drop everything from the comma "," on).
 
This ought to get rid of currently unreachable and uninterested
subscribers. They'll be sent a default message that is relatively
clear to understand. Or, if you choose to, you can edit the notice
to be even more clear (make sure you grasp the "real" meaning of
the default message's comment about "forward" vis a vis "reply").
GET <listname> MAILTPL (if there is one), or else
GET DEFAULT MAILTPL, and cut out the section starting with:
>>> RENEW1 ...
down to but not including the next line beginning with >>>
 
Edit the message to suit your needs, and add a line at the top:
PUT <listname> MAILTPL PW=yourpersonalpw
 
where "yourpersonalpw" is one you created by sending LISTSERV the
command:
PW ADD yourpersonalpw
 
Mail the <listname> MAILTPL file to your LISTSERV
You, of course, should be an owner of <listname> or LISTSERV admin.
 
Peter R