Liz,
 
My ferrets have the run of the house and though they use a litter box they
still have accidents.  I tried several cleaners none that really worked
100%.  I finally called a professional carpet cleaning service and they they
did a great job.  Areas that I thought would never come clean again look and
smell like new!
 
The cost was more, about $60, but well worth it.
 
Bob
[Posted in FML issue 1810]