Cupro is a regenerated cellulose fabric made from cotton waste, specifically the tiny silky cotton fibers known as linter that stick out of the cottonseed and are too small to spin. The linter is dissolved into a cuprammonium solution, which is a mixture of copper and ammonium, dropped into caustic soda, and then spun into fiber. Cupro is also known as "cuprammonium rayon," "ammonia silk," "cupra," or "Bemberg". It is a popular semi-synthetic option produced almost exclusively in China. Cupro is said to have all the positive qualities of silk, including its silky-smooth texture and draping ability. It is often used as a more ethical, vegan-friendly alternative to silk. Cupro is a by-product of cotton production, so it is technically a recycled textile. However, its production process involves toxic substances such as copper, ammonia, and caustic soda, which can be harmful to the environment and workers if not disposed of properly. Cupro is considered a fairly sustainable fabric overall, but it is not perfect.