By all means wash it first. I bought some one time and when I washed & dried it , it was a wadded up mess. It was so hard to iron that I decided not to use it except for non washing projects. There are many different grades of muslin on the market so be choosy. I think what I got was almost homespun. It was ruff like too. So before you put it on a very nice top be sure what you are getting.

The majority of my quilts are backed with muslin. I buy the 108" or wider by the bolt, when I find it. For whatever reason the two quilt shops in my area don't carry any muslin. UGH I think for hand quilting muslin is much easier on the fingers.

Yes. Have used muslin on a lot of quilts that I have made in the past and have always had good results.

My aunt only uses unbleached muslin for the backs of all of her quilts and has never had a problem.

Just wondering if there is a particular weight or thread count that you guys like the best? There seems to be different ones. I was thinking about using some muslin on my next project.