are you asking because you've seen info that "quilters cotton" is tighter weave and hence better in face mask in keeping out Covid 19? If so, a friend that owns a LQS has told me that most "quilter's cotton" is actually only about 70 thread count, while most cotton sheets are 150 up to 500 thread count! Some of the cheaper "quilters cotton" is actually only 40 thread count and may often have heavy dye and sizing to give it "body"---but you'll know that cause it's likely to be stiff. Probably the best combo for face masks would be batik and nice cotton sheets.