A cautionary tale: Wool is NOT my friend.
After completing my duster knitted from Berroco Peruvia that fit perfectly, I put it in the washing machine with the setting at cold water, handwash delicate cycle thinking it would firm up my stitches and remove the "wooly" smell. I was horrified to find that one side felted beyond repair -- although I used cold water, I think the gentle agitation added to the unwanted felting process. The whole thing is wasted and now I'll painfully cut off my fancy buttons and save for another day.
You may know this already, but PLEASE learn from my mistake and only hand wash your wool duster.