I mix it as per the instructions. As for how long to soak it, that all depends on how dark you want to make it. Keep in mind that some plastics will accept the coloring better than others. I have had some of my canopies in the solution for a couple of hours. I would also say that once it has dryed, it is fuel proof. I have never done anything to mine after dying, and they have never run or faded. Just be careful with the dye, as it will stain anything that it comes in contact with. Good Luck, Dave