I found a cheap $6 black light (or rather UV) flashlight on Amazon. Once it arrived, me and my daughter went out on the quest of finding what glows best in it. Basically some sort of phosphor that absorbs the UV light and emits visible light making it seem to glow in the dark.
Based on a quick bing.com search we tried a bunch of stuff, but what worked best is laundry detergent. I knew that to make clothes seem bright these have phosphors in them. The indirect proof was how bright a newly laundered T-shirt was glowing. Until I popped open one of the Costco laundry detergent pods and put it under UV light I never could’ve guessed the intense glow they emitted.
Enjoy a video of that.