I remember my mum used to put all leftover soap together and the result was a very colorful piece of soap that she gave me to make some sculptures from it. I liked carving and creating small figures out of the leftovers. Apart of this, she used old soap in the washing machine or she put the leftovers in that special device in the closet, to make some bubbles and clean the toilet.
site there are some tips also about how to reuse leftover soap bits
: if you will mix the soap with glycerin and melt in the microwaves you will find out that you just
created a hand soap. Other creative solution would be to put the leftovers
in a sock or cloth bag and use it as a sponge during shower. What about you? How do you manage with this issue at home?
Picture from here.