Good suggestions! My vote would be for Kleenex, Puffs, or other disposable tissues. If it were put on at the factory, there would be no evidence of tampering. Since Kleenex is usually thrown out after use, there is no evidence. It could even be Kleenex at the beauty shop...hence no anthrax in the house. Dittos for the lady who died in New York.
Very scary. I have scared myself!
Your Kleenex Puffs theory is worth sending to the FBI as a suggestion. I was thinking that the spores could also be put in talcum powder then returned to a store (like the Tylenol) but I'm sure the HazMat people would have checked any that was in her home.