you can mix them in at the end just before you pour(thick trace so they don't sink to the bottom after you pour) for some mild scrubbiness, also a contrasting color against a plain soap looks lovely. You can sprinkle them on top of a texturized top to add interest, or mix them just into one layer of soap for a different look. You can mix them into a sugar scrub for color/scrubbiness, you could sprinkle them onto bath cupcakes for interest...