Tarnish.. is that when copper gets green? because this looks a lot like that :) I like the effect!

Ajax made a slime shader that is great for putting slime or mould on things. It's in his free shader pack that AFAIK is still available in Free Stuff. Although it's a few years old (made for Poser 5) it's still great. And perhaps you can get some ideas from it to incorporate in this one :) Just an idea of course. This is already great!

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You just can't put the words "Poserites" and "happy" in the same sentence - didn't you know that? LaurieA
  Using Poser since 2002. Currently at Version 11.1 - Win 10.