A rigger brush, a thin wash and capillary action are all used to get dirt into all the edges and corners of panels, doors and windows. By dipping the brush into clean thinners (white spirit) and then into the wash (MIG Productions Dark Wash), a good volume of fluid is ready to be transferred onto the model. The inevitable large blob on the end of the brush is removed by touching the tip against the rim of the bottle and the tip is then gently touched to a corner of a panel or junction of door shut line, window, panel, etc. Capillary action will take the fluid from the brush and run it into corners and along edges as if by magic.