The best way I found to switch litter type is the same way you switch
food: gradually.  Start by sprinkling just a little of the new litter on
top of the old, not completely cleaned litter.  Over several days,
increase the amount of new litter.
 
By the end of the week, you have (hopefully!) converted your ferrets with
minimal digging, playing and stealing!
 
Linda Iroff
Oberlin OH
[Posted in FML issue 3564]