Once upon a time, when I was new to painting miniatures, we had an Orcus.
Orcus had some kind of unfortunate paintjob done at the hands of a Chinese worker. Instead of looking like the good promo art above, he looked sad.
On top of that, the little nubbins on the bottom of his wings looked really good in the picture - however, the person who sculpted Orcus seems to not have understood they were gathered wings. He ended up with butterfly tails, with big flat bottoms.
The Prince of Undeath needed to look a little less...fabulous.
The first step was de-basing him and cutting off his wing problems. To do this, I had to use an exacto knife to actually pull his wings off.
I wish I had taken more pics! Orcus' wings were actually attached in a hole in the back as one giant piece. As a result, it looked like he was wearing a backpack. I had to pry the wings out, and cut away almost all the middle part so that it actually looked like he had two wings instead of some kind of messed up harness attached to his back.
I used an exacto knife to whittle down his wing veins too, they were popping out really far. I then used greystuff to rebuild his wings in the back, so that it didn't look all broken up.
Then I built him a base from Sculpey! Seeing as Orcus is from a frigid layer of the abyss, I decided to make it an ice-themed base and just kept his original D&D mini vinyl base he came on. I built it up with Sculpy, and found an old plastic skeleton miniature I had - I tore him into several pieces, planning to work Orcus' title into the base, too.
I also gave him his tusks. The mini is missing them, and without his scary tusks he looks like a wolf. :(
I made some broken ice-floes by rolling out a small sheet of Sculpey and breaking it apart with a hammer, then arranging the pieces.
His paint job began with a thin layer of black primer, and worked with VERY THIN paints to begin working up Orcus' colors.
The main problem with repainting D&D minis, and the place you need to be cautious, is that they are pre-painted. You can't really strip them without causing slight to massive damage to the vinyl WOTC used, so you have to be very careful and make sure your paints are very thin.
That's more like our Orcus now!
I threw the references of the original miniature out the window, and instead just used his pictures from D&D 3.5 as color references.
Did you realize the area around his belt, at the crotch area, is actually supposed to be his skin? The original paint concept doesn't touch that, but the picture in BOVD shows it clearly.
His wings look like wings now! Hooray!
A closeup of the ice floes and skeleton. I tried to make the skeleton look like an undead, with glowing red eyes. Poor thing is stuck in the ice. :(
The water under the ice is painted as such, and I used drybrushing to try and emphasize its iciness.
I hope this can be helpful in you restoring your miniatures!