A wash is very thinned paint 10:1 is a good starting point, with a drop of dishing liquid. The dishwash liquid breaks surface tension and helps the wash "flow". A wash is applied sloppily. Dont be afraid, although I do recommend maybe testing on a scrap armor piece. Capillary action will draw the paint into recesses, around raised details and into any panel lines. If you apply it to heavily or if you dont like it for some reason, it can easily be removed with a damp cloth. Then repeat until you have the desired effect. For my TD I used the hair spray and fullers earth technique exclusively. I prefer washes and dry brushing techniques for Mandos for example. Just my thoughts and YMMV of course.