Originally Posted by
patchy-at-best
Snip off a scrap, hold with tweezers and burn that lil sucker. If it melts back onto itself, even a bit, its a poly blend. If it just goes black, brittle and ashy it's cotton. If its a poly blend it will never soften. If its cotton, there's hope. Did it shrink at all when you washed it? Soak in vinegar overnight then wash in hot water. If that doesn't work, its been over treated with sizing and no good. The only way then for a softer outcome is to use a few layers of flannel and chenille cut it.
I've found that 100% cottons burn to a very soft ash that turn to powder.
So does rayon and wool, for that matter. I don't know about silk, because I've never burned any.
Anything that contains nylon, polyester, dacron, etc - will leave something crunchy or gooey - and the "remains" stay hot much longer than the ashes from the natural fibers. These things frequently burn with black smoke, too.