Muslin is a basic/ utility fabric used for many things. It becomes softer and softer with each wash and holds up well. It used to be used for quilt backs all the time. The difference between bleached and natural is bleached is white. There are a vast variety of ( grades) of muslin-- very thin, loosely woven to nice, premium ( weighty) higher thread count muslin. For quilting li
ook for ( premium ) or medium weight in the descriptions. I purchase mine from fabric.com. The bleached is wonderful for dyeing your own fabrics-- it takes the dyes very well. I use a lot of muslin.