Eco-Design Green Design Recycle Your Urine to Make Invisible Ink, and Other Fascinating Uses for Pee By Sami Grover Sami Grover Twitter Writer University of Hull University of Copenhagen Sami Grover is a writer and self-described “environmental do-gooder,” now advising community organizations. Learn about our editorial process Updated February 5, 2021 Share Twitter Pinterest Email Ajay Tallam / Flickr / CC BY 2.0 Eco-Design Tiny Homes Architecture Interior Design Green Design Urban Design From peeing in public to the shared flush, I've written a lot about all matters toilet related. So much so, in fact, that for a time I was known as TreeHugger's official "pee and poop" correspondent. But urine gets stale after awhile, so I took a break and wrote about some other stuff instead. Luckily, however, others are carrying on the tradition. And Shaun Wheatcroft over at RedShed has written a great post outlining 10 great ways to recycle your wee. (Yes, he's a fellow Brit.) From peeing in your compost to making fuel (or drinking water!), some of this stuff has been covered before. But there are some new uses here too. Apparently Ancient Roman spies, for example, used to use pee as invisible ink—originating the phrase "read between the lines". Other uses include cleaning your garden paving, reviving the color of your garden furniture, or making glue to fix broken metal. I doubt that many of these ideas are going to gain mass adoption (almost every time I write about this stuff, I invariably get comments from disgusted folks who are outraged at us dirty treehuggers), but that's really not the point. The point is that urine is a useful resource which we treat as a hazardous waste product. And rethinking its value can remind us that so much of what we throw away could be used for the good if we'd start getting smart about waste. Besides which, we don't need everyone to become back-to-the-land hippies to start benefiting from this wisdom. As long as it can overcome current design flaws/user education challenges, mainstream (sorry!) pee-cycling can harness the power of urine without asking the squeamish to get their hands dirty. It's time to get serious about our bodily waste.