joss sticks are a type of incense. they are traditionally burned before an asian religious image, idol, buddha statue, or shrine. but some joss stick burning rituals (and the prayers that come with it) do not need to be done in front of religious images. they can be burned before anything without limits; like in front of a door, or open window as an offering. in modern days, the burning of joss sticks can be used for any reason, like making the smell of a room better or lighting fireworks up.