If you have cats you know how many buckets of cat litter you can go through. Instead of throwing them away why not grow some mushrooms out of them!? They are PP5 food grade which is suitable.
I use cold water pasteurization to prepare the straw substrate, mix the straw with mushroom grain spawn, and layer them inside the buckets. The buckets have holes in them from which mushrooms will grow out of.
You can also grow mushrooms out of laundry baskets using the same method! Check it out here: