Water is great when you need to soften something inside, like the inner pegs on the butterfly joints. But water can be annoying when it stays in crevices. I used to note on Fwoosh every time I had a figure/accessory that wasn't water-tight, like JADA's Hadouken mold, until Robo made fun of me. Lol. Anyway, I've found that using hot air on the figure while it's in a container like a big coffee mug works great to evenly heat a figure without the mess or lingering effects of water. A second compressed air gun to cool them down is very helpful and the whole process ends up quicker than using water.