Mind you, I don't weather my minis. When done well, weathering looks amazing, but more often it ends up looking, in my opinion, pretty terrible. Really, really terrible.
So, expectations for myself are pretty high... but this is a pretty safe place to try it out on. It's a piece of scenery that I can strip back down without too much trouble, not a freaking army.
I've played around with a couple of approaches. Unfortunately, I've stripped and repainted over some of them before I realize I've done it and forgotten to take pictures.
A Gentleman's Verdigris
Probably the best (and only) great verdigris tutorials come from b. smoove. He's got two, in fact: his Chaos Marines and a darker, greener approach for Ogres.
I haven't quite followed his walkthroughs to the letter (I was working on it and got test models mixed up and switched halfway through: d'oh!). Here are some results from, following some of his steps.
Look at the backpack here. This is kind of a halfway: my usual brass (Shining Gold -> Burnished Gold -> Devlan Mud) and then wrapping up the AGO Ogre way: a wash of Dark Angels Green and Scaly Green followed by a Burnished Gold drybrush.
These look ancient and evil. Really nasty. It's really a great freaking effect.
I like this look... but not for the statue and not for generic patina.
Also, after an extended e-mail exchange by the unbelievably helpful Mister Justin asking for his advice on how one would go about using weathering powders to get verdigris, I went ahead and ordered his Oxide Weathering Pigments. (It's interesting: there are a ton of videos bouncing around the internet on how to use pigments for rust and, the best of my knowledge, no videos about how to use pigments for verdigris.)
Here are some examples of unskilled efforts to use the oxide powders:
This Tin Bitz with a heavy, heavy Brazen Brass drybrush followed by some stippling of the various powders.
The same stippling of powders, but this time over my usual Brass recipe (Shining Gold -> Burnished Gold -> Devlan Mud).
Even though I'm basically at monkey+football stage with this I think it convincingly ages the mini. It looks like the real stuff.
And yet I'm not entirely happy with it. It looks like real patina except, in doing so, it kills the illusion of scale. I mean, basically, the reason we paint these little dudes is to make them look like they're not a couple of inches tall... and this patina makes them look like extremely little aged statues, not aged statues at a different scale.
Where I Think I'm Going
I think these two approaches aren't working for me because patina works a little differently. b.smoove's approach (and every other approach I've seen on the internet) is based on getting the green/turquoise in the deep spots, via a wash. But, Googling around shows that, really, that verdigris is really on the high spots, not the low spots.
I think that's part of where the powders are failing me, too: rust collects in the crevasses, unlike patina. brushing and wiping this stuff on the smooth spots is a lot harder than the details, you know?
So, I think I'm leaning more towards a dry-brushed verdigris approach. Color-wise, I'm going something more like the Oxides: lighter blue-green.
Here's a half-baked attempt at what I'm thinking. (Look to the head, flamer and pauldrons.)
I think I'd have to go a bit (but not a ton) heavier.
What's interesting is that the right leg (the one I haven't really drawn attention to) is almost perfect in the way it covers the area (if not the color): but I can't remember how I did it! I'm pretty sure it was one of the b.smoove washes (cut with some forgotten combination of Future, water, matte varnish and rubbing alcohol) followed by an, "Oh crap! I didn't mean to wash that!"
Anyway, this is what I'm working with at the moment. I'll continue to share my progress. We'll see what I end up with.