Here's a test picture of the mud effects I've done on my Defender. I was going to wait to get some PVA glue, but seeing as bills come before games (most of the time), I had to improvise. They say necessity is the mother of all inventions, so here you go. Sand, flocking, Reaper Miniatures Walnut, RM Wood Shade Ink, RM Flesh Shade Ink. Mix until it's a nasty pasty mud, and apply. Viola!