Kenny, with a hobby knife, just scrape off some chalk from the color you want on to a paper towel. Then apply lightly with a dry very soft brush (a rounded edge make-up brush works very well but a soft rounded paint brush is fine) to see how you like it. Apply vertically only. If you do, you can always apply more.
The wet technique (dipping a brush into a little water then into the powder) is better for use on "metals" (like the fire escapes) to indicate rust that is peeling because it will create a textured rust effect.
Jerrman
