Tiny plastic particles are considered pleasant-feeling skin-scrubbers and tend to have a smoother effect than natural ingredients, like nut shells or salt. Different microplastic ingredients in cosmetics have different functions, for example film formation or viscosity regulation. The cosmetics industry uses microplastic ingredients because of these functions and because microplastics fill up products at a low cost. In some cases, up to 10% of a cosmetic product may be comprised of microplastic ingredients.