Tinder was made by charring or partly burning linen or cotton rags.
火绒由木炭或者部分可燃的亚麻布或棉布制成。
英语百科
Cotton paper
（重定向自Cotton rag）
Cotton paper is made from cotton linters or cotton from used cloths (rags) as the primary material source, hence the name rag paper. Cotton paper is superior in both strength and durability to wood pulp-based paper, which may contain high concentrations of acids.