Paint is one thing, but inks/dye is another. When painting paper is easy, painting non-porous surfaces is not. That's when you want to use ink like alcohol inks. They create Neat effects and not one of them comes out the same so it's great for OOAK work. Use alcohol inks with alcohol for a marbling effect. They DO get messy, so you'd want to use gloves and a protected surface but that basically goes for anything when you're crafting, really. And although the colors are nice and brilliant, sometimes they come out more translucent so you need to use more of the ink.
