Add metallic dimensional details with a palette knife through a stencil or just with your fingers! Can also be thinned with water to use as a metallic paint AND it dries waterproof (so you can paint or rubber stamp over it without bleeding). See a techniques video.
Teri Calia made a Dia de los Muertos Cat Mermaid Shrine (see the wide photo below). More info in the blog and/or see the supply list.