Embroidery on Hankies

I spent all morning and half of the afternoon embroidering on these hankies.  They all are very old and the fabric needed delicate handling but had to withstand the embroidery needle.  I practiced on some flimsy fabric that I had and decided to try Terial Magic, a stabilizing fabric spray.  I had read that it causes yellowing and I got some water stain looking spots.  But it gets very, very stiff and allows the stitches to lay on the fabric without pulling.  All of the Terial Magic washed out without a problem. I will have to try the stuff again on another project.