fetchmail can't delete a fetched email

Greetins all;

My isp seems to handle a request into its mailserver, which I believe is 
dovecot, in pop3 mode, by disabling fetchmails housekeeping cleanup of 
successfully fetched emails, so in a days time I have seen 450+ emails 
pile up, the I have to log into that same server with a browser and the 
browser can then delete these msgs 100 at a time.

Is there a keyword stronger than "no-keep" that can override its 
inability to expunge read messages by using the same expunge method a 
browser uses?

Thanks all.

-- 
Cheers, Gene Heskett
--
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>