This is a photo from an actual Secret Waterproof Deodorant demonstration we witnessed.
The demonstrator put a bunch of Secret Waterproof Deodorant on a hard-boiled egg, and then dipped the egg into a bowl of blue dyed water. She held it there a moment, then removed it. As you can see, the egg turned blue, except for where she applied the deodorant on the top.
This is proof, we think, that it works. It was pretty weird, though.
Apparently, they like to demonstrate on hard boiled eggs because the surface of an egg is porous, like human skin. The white color is easy to see and differentiate from where the blue water seeped into the egg.
Did it leave a white residue? That, we do not know. But it totally waterproofed the egg. Awesome. Swimmers and beach bunnies take note.