The battle damage was painted using the blister foam technique. If you're unfamiliar with this technique, check out the tutorial I wrote:
http://handcannononline.com/blog/2011/07/25/tutorial-advanced-that-one-hurt-painting-battle-damage/
Really wonderful job on this model. One of the best Slayers I've seen. Weathering tut very good as well. Wish the base were as impressive as the paint job. Glow is very well done also. Great stuff.