Take some salt and put it in your bowl
Next, add your lemon or lime juice if you have any
Add a few drops of bubble bath or shower gel so that the colour stay, but the salt stays pretty much dry.
Leave it out in the sun, somewhere like a window so that it dries a lot.
Use in the bath, and as well as smelling yummy, it also created bubbles in the bath!
Have fun relaxing! :D