I have no idea what a Pendleton wool shirt is. I have however, made quilts out of clothing, wool, velvet, you name it. Before I even cut them up everything goes in the wash, dry as you would normally (we tend to line dry here). You will then see how they survive and if they have any instability with colour etc. Woolen fabric makes beautiful quilts...good luck with yours (and don't forget we looooove pics.).