Snake oil will keep the water off - excellent brand name idea for it!
You can throw your phone in a toilet, and it will still work. But I'm not cleaning it for you.
Most are IP67 or better nowadays, inc your iPhone.
All we need now is for someone to design a phone with built-in bumpers on the corners, instead of always having to buy a case.
Bit like buying a bike with no engine bars. Oh.