While it's become difficult to find direct listings of ingredients used as fillers in detergents (just references to soaps with 'no fillers'), the general consensus seems to be that ingredients such as lime stone, chalk and animal bones are all used because they are calcium based. Calcium works along with phosphates to increase suds in the water, and make you feel that your laundry is clean. Fillers also add bulk to the product. These fillers, however, leave clothes dingy and contribute to itching, allergic reactions, and pre-mature fading and wear of fabrics. Norwex laundry detergent contains no fillers, perfumes, or dyes.