Nanomaterials-filled plastics are becoming increasingly popular, but so far they have been mainly concerned with their production and quality testing is still in its infancy. Some companies offer specialised equipment to determine the properties of materials containing extremely small particles. The recycling of plastics recovered from waste can only be successful if the regranulates are subjected to the same rigorous quality control and meet the same requirements as fresh materials. Fortunately, existing testing methods are adequate for this purpose.