keep my mailing list updated

hi everybody,

My aim is keep my mailing lists updated. 

With a simple procmail recipe  I can get the addresses from the returned mails 
sent to the list but I am not sure if it is possible to pass these addresses to 
a script file. The idea is that script file to delete these addresses from the 
list file.

As you could guess the idea is to eliminate the old addresses that no longer 
exists.            

Thanks for your time folks