One can do a burn test to see if the fabric contains a synthetic:

One only needs a piece of fabric about 1/4 inch wide by about 1 inch long - doesn't take much

Hold it with tweezers in a flame - I prefer a lighted candle - make sure that you have an ashtray and a glass of water handy

If it is synthetic, it will burn with black smoke and leave either a crispy or gooey ash.. The residue stays hot for a long time, even after the fire is out.

All cotton burns with only a little smoke, and leaves a very powdery, soft ash.

I've used them in quilts (they hold up so well), bags, totes and table runners

And sometimes it can be like a small knob of plastic.

Glad to know someone else doesn't follow rules easily, I make mine up as I go!

I use them for gift bags.

Me too. I would love to be able to find more for my dresses.

Pretty much gave any might have had away. Don't even like to wear any poly anything, and hate the smell of ironing that fabric.

I recently donated a big box of double knit that was my Mothers. She made many quilts from double knit but at one of the quilt shops a local quilt guild ask for donations to make hats for cancer patients. That what I wanted for that fabric and I know my Mom loved that I donated them to such a worthy cause.

i use it for backing, mug rugs, table runners, bibs for the grand kids, for the small projects i do

Once in a while I purchase a T-shirt that has a small amount of Poly in it because it is a color I need. Other than that, I never purchase anything with Poly in it. I guess I am just "a cotton snob". I took all my Poly fabric to Goodwill in the 90's and never looked back.