What an age old problem.  I'd like to recommend a flea comb.  This is a
noninsecticidal natural method for treating the animal directly.  And the
benefits are wonderful for both ferret and human.  I've seen a big decline
in our fleas, however, to totally elimate the pesky little blood sucking
fleas you will also need to treat the environment - inside and outside.
The flea comb is a metal (metal works better than plastic) comb with very
close teeth to catch the fleas when you comb through the fur.  I've found
that when I place my thumb over the flea on the comb it stays there till I
dump it in the glass of soapy water.  Did you know fleas can't swim?  I
consider myself a compassionate soul but I must admit I do not feel a bit
guilty about drowning the fleas.  The ferrets have come to really enjoy
the process and I like it too.  It has a calming effect on all of us and
the ferrets are being purposely handled individually.  I have two combs
and each evening a volunteer and myself watch t.v. and talk as we flea
comb whoever comes by.  I'm thinking of having visitors comb the ferrets
too.  An enjoyable experience for all of us!  Hugs to all.  tle
[Posted in FML issue 1234]