I just finished hemming (thanks to stitch diagrams on here a few weeks ago) a Stillwater acrylic to shorten it. Had to cut off a bit of the fringe/flap to keep the hem from being too bulky. I put it in the fireplace for a test. Yes, it burned, but slower than I anticipated, and was not at all flashy.

btw, I had no concept of how big a job that turned out to be. Took a lot more stitches than I would ever have imagined. Worked out OK, though.