The special fabric is specially designed for the Pet Loo, with small holes to allow your pets urine to properly drain into the waste container. The grass only needs to be replaced when you feel its necessary. To clean up your pets waste, remove the waste container and dump the urine in your toilet or yard. The waste container holds 2 liters of liquid and is made of a material that reduces odor. For even easier cleanup, place a Pee Pod into the waste container. These disposable pods are lined with our Wee Sponge powder that solidifies into a gel when it comes in contact with liquid, effectively trapping urine and odors. For your pets solid waste, use a pooper scooper or a poop bag.