Ziory Unisex European Oversized UV400-Shining Plastic;Polycarbonate;Acrylic Fashion Classic Sunglasses (Black and Grey, 1695) Product maintenance: please hold both sides of the lens and rub it gently. And please don't rub it hard at only one single side. Clean the lens by water or wipe them by the soft cleaning cloth included regularly. Do not use alcohol or any other chemicals to clean the lens, to avoid surface broken. Do not maintain the sunglasses in such environment of high temperature or long tme damp, to avoid deformation.