In my humble opinion, you have nothing to lose by trying it the way you planned. I once used spray oven cleaner on a pair of jeans I had gotten paint on. My theory was: the jeans were already ruined so why not try it. The paint came out without harm and the jeans were worn for many years. On your towel, to keep it from continual fraying I would add a line of machine stitching around the towel.