You might check a web site that concerns itself with sewing fabric, there
are burn tests to determine the difference between natural and synthetic
fabrics. They involve checking the color of the smoke and the ash and
also, i think, the texture of the ash. I can't give a site as i don't
have Internet access.  Another place to look would be a site that
concerned itself with Civil War era reenacting, using natural fibers is
very important to these people.  I hope this helps.
Knox Adler
Marthasville, MO

On Mon, 9 Dec 2002 12:41:49 -0500 Milt Lathan <[log in to unmask]>
writes:
>Didn't I see a test here for determining whether burlap has plastic in
>it?