Silk hankies are one of those amorphous fibers that can do lots of things, and do them well. You can, of course, spin with silk hankies. And they are great for learning to spin, since you pre-draft the hankie and then just add the twist. Very controllable.
You can also knit silk hankies without spinning beforehand. Simply draft out a hankie (how much you draft out depends on how thick or thin you want your yarn) and knit away. It makes a beautifully soft, supple and lustrous fabric. And since it is silk, the yarn is actually quite strong.
Felting is another option for working with silk hankies. They are perfect for nuno felting - you can make scarves, flowers, garments and more.
The sky's the limit when it comes to options for creating with silk hankies.