We used a product called VetChem (I believe that's the spelling).  It's
an area spray, available at vet's.  It did a great job of killing fleas
in carpets and furniture.  We removed the ferrets from the area;
sprayed carpets, rugs, furniture, drapes, etc.; let it dry, vacuumed,
and returned the ferrets.  We repeated this in 10 days to get any eggs
that might have hatched.  It worked great.
 
Dick B. 

[Posted in FML 5398]