I sympathize with your plight, David.  My youngest ferret, Rascal, preferred
to use her litter box as a sandbox.  Even after I would scoop some of her
"mistakes" from around the cage into the litter box.  She kept this up for a
few weeks.  I would scold her whenever I would see her "playing" in the
litter box.  Sometimes I would have to just pick her up out of the litter
box and put her somewhere else (preferrably near some toys).  She still digs
in the litter box just after I change the litter but that's it.  I think if
you keep at her, KIT will learn not to play in the litter box.  Good luck!
 
Marc Wilson, Slinky, Bandit and Rascal
[Posted in FML issue 1413]