To use simply brush the surface with a good coat of crackle medium. Once it is completely dry paint the surface as you like, and the cracks will appear in minutes.
The cracks work best with contrasting colours. So for example if you are working on a Dark surface use a light paint, and on a light surface with a dark paint.
Brushes can be cleaned with water.
Great for Decoupage touch ups or to give your MDF project an antiqued finish.