Indoor cats need to use a litter box in order to go to the bathroom in the proper place. However, cat litter is full of dust that is dangerous for humans and cats to breathe. In the wild, cats go to the bathroom in dirt and soil. You can replace your normal cat litter with potting soil and sand if you don't mind the mess the soil will track around your house.
Select a location for the new cat box that is quiet and located on tile or linoleum for easy clean up. Cats need a private place in which to do their private business.
Mix 2/3 potting soil with 1/3 sand and fill the cat box half full of mixture. Shake the box from side to side to create an even layer of the soil.
Change the cat box twice daily and remove all of the urine and faeces to ensure your cat has a clean box.