Thanks DK, I just got back in town tonight.The weathering was done using the salt technique. Prime with browns and oranges, semi gloss sealant, damp the model with water, sprinkle on salt. Then I sprayed on green and subsequent layers adding tan with an airbrush. Brush off the salt, leaving brown chips behind. Seal again, using thinned down oil paint, I defined the shadows in the crevasses. Hope that helps.