There are several simple ways to identify the pros and cons of fiber products (baths, cotton pads, pillows, etc.). The high-quality cotton has a white color and a good hand feeling. It has a certain elasticity when it is gently pulled out, and the "black heart cotton" looks like impurities and has a rough hand. High-quality cotton has no pungent odor when burned, while "black heart cotton" has a distinct pungent odor. If the batt is made of chemical fiber, the raw material should be produced by the chemical fiber factory. This normal chemical fiber generally has a uniform color, a certain length (usually 20 mm), no excessive dust, good elasticity, and no odor. If the cotton wool is miscellaneous and even contains yarn ends and rags, it is likely to be inferior "black cotton" produced by secondary processing of industrial waste.