After the "white armor" look of the silver leaf, this is a technique capable of more subtlety. I took a light gray armor and black grilled helm and spray painted them black. Why spray paint the black helmet black? To give the surface that is more receptive to the metal treatment - it is much more difficult to control on bare plastic, nor will it stick as well.
Plastic usually has some kind of mold release that needs to be cleaned off for paint to stick well. It's best to put the pieces to be painted into some warm water with some mild detergent. Let it soak for a while (I usually do it overnight, but I doubt it needs to be done that long). Rinse the pieces off, make sure they are dry, and the paint will adhere better. Here's the basic prepped figure - which some may like as is:
Rub'n Buff comes in a tube and like the silver leaf, can be found at most arts and crafts stores. It's comes in a variety of metal colors (silver, gold, copper, etc). It's basically metallic powder in a soft wax base that you apply sparingly with a cloth. I actually just use my fingertip (wash hands thoroughly and don't eat anything with your fingers afterwards). Let me reemphasize sparingly - this is kinda like dry brushing. You should not be putting this on like paint - your applicator (cloth, finger, whatever) should be barely stained. It's best to start with too little rather than too much. It's probably best to have some kind of sealant coat applied, but I haven't done that yet.
And here's the finished piece with the armor remounted on a fig. I far prefer this to the silver leaf look, which is a bigger pain to do and easier to screw up. Barbie Blue armor will not survive intact in this house!
