you could check out the cookie crumbler extension for firefox...but that one takes an entire click and it's not IE (which is a good thing but that's a different thread...)

another lame, untested but only maybe effective method is to create a script to delete the cookies and then run the task every minute or so

http://www.userscape.com/helpdesk/in...=kb.page&id=23

probably best would be to script the delete and then use cron for win

http://www.kalab.com/freeware/cron/cron.htm

you'd just need to figure out which cookies to target in the script (or all of them?)