Joint compound, also known as “mud,” is used by builders to finish the seams between pieces of drywall. After drywall is nailed up, paper “drywall” or “joint” tape is used to cover the gaps between adjoining pieces of drywall. Joint compound is spread over the tape to create a smooth, continuous wall surface. Joint compound may need to be applied in several coats, with each coat being allowed to dry and then sanded smooth before the next layer is added. Joint compound can also be used to patch cracks, fill small holes in plaster or drywall, and smooth over rough spots. Historically, some brands of joint compound have contained asbestos. Asbestos filler was used partly for its flame-, moisture- and insect- resistant properties. Asbestos was also used in these products for its thixotropic properties. That is, it helps give the joint compound a smooth, easily spreadable consistency, without changing the product’s basic nature. Joint compound could be purchased as a dry powder, to be mixed