Cecilia
 
What I have used for many years works very well for me.  I drill a small
hole in the back of the litterbox and then attach the box to the cage using
a cable tie.  When the box is ready to be changed, clip the cable tie and
reattach when clean!  This is a cheap easy alternative to chasing the litter
box across the cage.  Some folks call this thingamajigs electrical ties or
box clips.  Binder clips will work well, too as long as you get the big
ones!
 
Lisa, Head Ferret
The Ferret Haven "By-the-Sea"
[Posted in FML issue 2292]