Brown glass bottles can be used for skin care products, such as serums, toners, or creams. Brown glass is a type of glass that is slightly tinted or amber in color, and is often used for packaging products that are sensitive to light. Brown glass bottles can help to protect the product inside from UV light, which can affect the stability and effectiveness of certain ingredients. They are also a durable and stylish packaging option, and can add a natural and rustic touch to certain products.