The worst that I've ever got on my kilt was coal smudges. How did they get there? Well, when I first had lessons in blacksmithing, the person teaching me was working a ren faire and said that if i was working with him at the faire i needed some sort of ren-type-costume, that was not synthetic fiber. Thus I wore my kilt, and a Jacobite shirt. I was good about not getting anything on it while working at the forge all day, and then just as we were breaking down to leave, i wasn't paying attention and smeared my coal dust covered hand on the apron of my kilt instead of the leather apron i had been wearing all day. *sigh* it took a long while to get rid of the spot.