I remember a post a while back from someone (sorry, I forgot who) asking
whether there was a ferret-safe way to eliminate roaches.  I used to live
in New York City (roach heaven!), and I got rid of roaches in several
apartments with a pet-safe chemical, but couldn't remember what it was
when I read your post.
 
It just came to me: BORIC ACID!
 
Sprinkle powdered (not granular) boric acid in cracks and crevices, across
window sills and doorways, and any other roach hiding place or access
point.  The powder clings to their abdomens and kills them.  It is safe
for people and animals (a boric acid solution is used as an eye-wash for
people).  But it really knocks out roaches!  I lived roach-free in NYC!
 
Hope this helps,
Nancy and critters
[Posted in FML issue 3236]