In this episode, we talk about Invisible Inks, an important concealment method, with Codemaster Cole, Al, and Dan. Invisible Inks are everywhere. You've almost certainly heard of them, or at least heard of secret ink or security ink, which is the same thing. There are so many that it is hard to know which ones to use, which is why we cover that in this episode. Plus, we talk about decoy letters, chemical reactions, Pliny the Elder, and introduce a shady character in the story.If you want to support the show, please follow us on Apple Podcasts, Spotify, or wherever you get your podcasts.Links:https://en.wikipedia.org/wiki/Invisible_inkhttps://kids.nationalgeographic.com/explorer-academy/article/invisible-inkThe Background music used in this episode is "Bio Unit", "Energy Drink", "Generator", "Pulse", "4 AM", "Disco Tokyo", and "Airflow", all by Bio Unit, and our theme music is "Mosquito" by Caspar Babypants.You can contact us on this text line. You can find Dr. Gareth's work at drgarethmoore.com. He has released many puzzle and cipher related books for kids, as well as a lot of stuff for adults, too.  Support the show