In this episode of For Flux Sake, I dig into a deceptively simple kiln question: do you actually need peep holes? We talk through what peep holes are doing in real life—not just “so you can look in,” but how they relate to venting, atmosphere, and how your kiln behaves during different parts of the firing. The big takeaway is that peep holes are a tool, not a moral requirement. Whether you leave them open, close them, or never touch them depends on what kind of kiln you’re running, how it’s vented, and what problem you’re trying to solve. We also tackle a listener question about glazing only the interior of a pot, which gets into stress, glaze fit, and why “it’s only on one side” doesn’t mean it won’t affect the whole piece. And at the top of the episode, Kathy shares research from Harvard Ceramics on historical graphite use as a ceramic sealer—one of those great reminders that people have been hacking ceramic surfaces for a long time, and the materials choices always come back to how porous/vitrified the body is and what you’re trying to keep in or out.