I was wondering about things like this too. My #1 son had some illegal fireworks that a friend brought into CA from AL. He put them in his messenger bag that he uses for school. I told him he's now contaminated everything that goes into that bag with black powder. Since the bag is fabric I think I'll just wash it and see if that removes the residue.

As far as the Walgreens bag, any glycerin based hand lotion that may have spilled would test positive.

ab53