Keep in mind that ferrets have very sensitive respiratory tracts. Choose litter that is non toxic, litter should be absorbency, fragrance free. If you ferret is post - op, choose a softer litter.
*Paper pelleted recycled paper is very good litter for ferrets if it is changed frequently. It has no odor of its own, is very absorptive, and is easy to handle
*Newspaper folded in the litter box. Drawback to this is that paper trained ferrets do not distinguish between their paper and your unread paper if it is left on the floor. Shredded paper is very hard to handle when it becomes wet. Harder to clean the litter box.
*Corncob litter and plain newspaper are not very absorbent and therefore will not absorb odor well either.
*Swheat scoop ferret litter - This is made from 100% all natural wheat. This product has tiny granules can be easily ingested. Ferret love to dig Swheat . Swheat is not easy to scoop, due to tiny granule size. More expensive than other litters.
*Wood shaving - cedar and pine is toxicity to small animals, that included ferrets. These oils release vapors, which then can cause the respiratory damage.
*Clay, clumping litter and some coarse clay litters are very dusty and can cause sneezing, especially when young kits ferrets dig and burrow in it.
If the nose is wet, fine clumping litter can get stuck up ferret's nose. Causing respiratory infections.
Fine clump litter can also stick to the ferret's butt causing infections. Such as, stick to the vulva of females, causing irritation and increasing their susceptibility to urinary tract infections.
*Clay litter is sticky! - This can cause the clay to stick to your ferret's feet, coat or behind as it scoots after doing its business
*The litter can then be ingested as the ferret cleans him or herself or may work its way into the anal opening and cause a block or prolapsed rectum .
*It can also get into the ferrets eyes, nose and ears if you ferret decides to go snorkeling in it.
*When you mix clay with any liquid - including urine, saliva, tears, etc - cement is formed. These chunks of cemented clay can cause a wide variety of health problems for your ferret including an intestinal blockage
*Clay litter produces dust. Ferrets have very sensitive respiratory systems and this dust can cause damage to the throat and lungs over a period of years.
*There are also other types of litter that can cause respiratory damage over time, not because they are dusty, but because they contain "essential oils". For example cedar, pine.
*Clay litter will dry out the coat
Most people on this forum uses, recycled paper litters and wood pellets Most cost effective litter is wood pellets.
Do a search in Housing section on litter and check out other litter reviews.
Good luck and I hope this helps
Respiratory toxicity of cedar and pine wood
http://trifl.org/respiratory-toxicity-of-cedar-and-pine-wood/