One tablespoon at a time, mix in the water. You don’t want it to be runny because it needs to harden. If you accidentally make it too runny, that’s ok! Just add more cornstarch.
Pour the mixture into an ice cube tray.
Let it dry overnight.
Gently remove the cubes from the tray. They are soft and break easily, so don’t twist and turn the tray too much trying to remove them. Just a little loosening will do the trick and they will come right out.
Place them in the shower with hot water and steam. They will dissolve releasing the vapors to help clear your nose!
Notes
Keep them in a pretty cup (as pictured) or carefully place them in jars and hand them out as gifts!