Today's re-organizing of my "stash" resulted in finding several
pieces of cotton/poly fabric which I won't use, and will list
later if there is any interest. Some are several yards long,
wide widths, suitable for backings? Utility / charity quilts?

I donated mine to Goodwill.

I use any fabric that is washable.....in my American Veterans Projects.....

Many quilters use poly/cotton fabrics. Don't count them out yet!

I have been doing to same and going thru what I will use and organizing.. the fabric I am sure I will not use I am going to have a barn sale this weekend and sell cheap to cover some of the cost and free up room for more. also deciding to part with some older machines I do not use and only dust them. I cannot believe how blessed I am with so much stuff!!