After the soap bottle was empty I tried washing it out but it didn't really work so I kept the water in and I shook it up a bit. It worked as water soap so I didn't need to add water.
This is how you make it. You need an empty soap container that still has some soap in it and you need water and that's about it. Then shake. And voila!
Ariel prophesied that it doesn't work. And she's wrong.