As you don't know what it is made out of, I would wash on the delicate or knit setting (if your machine has one) in cold water, and dry on no or low heat. If you don't have a delicate setting, hand wash in the tub. Use Orvus soap to wash it in. Orvus soap can be found in quilting shops or feed stores (yes, you read that right, FEED stores). It is cheaper at the feed store. Orvus is actually a soap made for washing the sheep before shearing, and the wool afterwards.