Making Holy Water

Listen, you smooth-brained mammal. You asked how to make holy water, right? Well, the joke is that “boiling the hell out of it” sounds like you're heating it a lot, which implies that the process is intense. And, "hell" is a place of heat which is funny because you need heat to boil something. But it also sounds like "hell" is being removed from the water, which then makes it "holy". It's wordplay, okay?