They use some rather consumer unfriendly chemicals, like formaldehyde as others said, but also things like flame retardants, pest deterrents, anti molding agents etc to preserve the clothes if they’re stored improperly. You should ALWAYS wash new clothes before wearing them, even ignoring the possibility of others having tried them on. Maybe consider another scent for your clothes.
Your grandmother’s sister is your grandaunt, and you use grand and great the same way you do for mother/father but with aunt/uncle.
So I think your fourth cousin twice removed was on the Thresher but someone may correct me.