Monroe Models Weathering Powders are self-adhering pigments that are great for making your models look weatherbeaten for added realism. Easily applied using a brush, they′re self-adhering so they won′t rub off like chalks. Choose from a variety of weathering colors to make your locos, cars and structures look dirty, rusty and dusty! WARNING: This product can expose you to chemicals including Silica Crystalline (quartz), which is known to the State of California to cause cancer.