These were made from a large piece of purple wool that was given to me. They could made from sweaters, jackets, etc bought at thrift stores or yard sales. There's all sorts of fun things you can do with wool. I have a book here from the library where they have fuzzed it/frayed it (not sure the exact word they use, some on the net call it 'felting') but once it's all frizzy, they wet it with a slightly soapy water, then mold it. One image in this book they do a booty on someone's foot. Once they've made the entire thing, they pull it off and allow it to to dry and it holds it's shape. Quite unique!
My kids mostly have knitted gloves right now, which is made like a sweater. They get wet instantly in the snow. I'm hoping these will help prolong their play over those knitted gloves, by keeping them dry a little longer since they're not supposed to be very absorbent! ;-)