Oil-Dri, also sold under names like SpeedyDry, is a kitty litter-like substance used to absorb spilled oil and automotive fluids. Oil-Dri can also be used as kitty litter, but there's a few tricks that a cat owner should know when using Oil-Dri as kitty litter.
Using Oil-Dri as Kitty Litter
Mix in the Oil-Dri gradually. Cats may stop using their litter box if the type of litter is suddenly switched, so when switching to a new litter or to a kitty litter substitute like Oil-Dri, it's important to mix it in slowly, over the course of several days. As the litter box is cleaned daily and the soiled litter is scooped into a trash can, add in an amount of Oil-Dri that's approximately equal to the amount of soiled kitty litter that was removed.
Sprinkle in some baking soda. As additional Oil-Dri is added to the cat's litter box, a bit of baking soda must also be added. Oil-Dri is extremely absorbent, but it does not have the same odor-elimination properties as kitty litter, so a bit of baking soda must be added to keep litter box odors in check.
Thoroughly mix the litter, Oil-Dri and baking soda with the litter scoop.
Continue adding baking soda daily. After one to two weeks, the litter will be largely or entirely eliminated from the cat's litter box, which will now be switched over to Oil-Dri. It's important to add baking soda to control odors. But for especially stinky litter boxes---like those used by multi-cat households---it may be necessary to implement twice-daily litter box cleanings or use a kitty litter box air freshener to control cat odors.