Dry brushing brings out details which might otherwise disappear by highlighting the raised surfaces.
Start by dipping the brush in paint then brushing off most of the paint from bristles. Lightly dragging the brush over the raised details leaves a very small amount of paint which highlights the raised sections only.
These special brushes can also aid in the application and positioning of Decals.
They can also be used for smoothing out any wrinkles or air bubbles.