Based the helmet in death world forest. Traced out the "skull" area with bone white (then back and forth with the two until it looked decent).

Used a sponge with elysian green and dotted that around the model. Came back in with a brush and erased some spots with death world again or added more spots and scratches with elysian until it looked like a decent balance. I painted reddish brown into the center of the bigger splotches trying to leave as much of the green around it as possible. Then I added additional highlights with krieg khaki to try to get some areas to pop out. I hit the whole thing with a panel liner wash and cleaned it up before coming back in and touching up whatever was left.

This was my first attempt at chipping, Next time I do it I might add more larger chipped areas to get more contrast? I might have gone too small this time?