Hello, fellow modelers! This is a Model Power HO ore car that I weathered with chalk dust. Here is how I did it: Using a screw, I scraped both gray and white chalk dust into a container. I then used a paintbrush to apply the dust to the model. While not airbrushing, this method is a fast way to weather that new shiny freight car, or add some dust to an old freight station. The possibilities do not stop there, however, and you can use this method on anything that you think needs to be weathered. Happy Railroading!