I recently bought two LARGE boxes of ties from the estate auction of a 93 year old quilter. More than 75 of them are labeled as all silk. Of the other several hundred ties there are labels on about 2/3 of them. I believe that some more are silk, but can't tell for sure. I don't want to mix fabrics in the projects I do with them. Some are cotton, wool, and acetate, but most are polyester. How do I determine the fabric content of the remaining 100 or so ties? Mostly I want to find those that aren't labeled but are silk.