When evaluating paper straw fabric, you must prioritize material composition and tensile strength. Ensure the fabric is made from high-quality wood pulp or recycled paper fibers that have been treated for moisture resistance. Key metrics include gram weight (GSM), which determines the thickness and durability for applications like hats or bags, and colorfastness to light (Grade 4 or higher) to prevent fading in outdoor use. Additionally, verify the weaving density to ensure structural integrity during the sewing process.