After getting to the end of your DISH BLOCK® dish soap bar, there can be little soap scraps left over. What can you do with these?
Here's how I use them up. I save the pieces for a while under my sink in an open container. These in the photos are a bit old, probably 3 year old scraps. 
Then, I add some water. Less is more, I dumped out about half of what you see here. If you add too much water the next step is harder to do. 
I use my CASA AGAVE® dish brush to agitate the soap pieces up and down and side to side. It generates bubbles, so now I have a bowl of foamy bubbles and a brush covered in suds.
Finally, I have my bowl of sudsy water, and I dip the brush in that to then suds up my dishes. The right photo is another small bowl I was cleaning.
The sudsy water is good to use for general dish washing, plus for cleaning out tricky things like bottles. Just pour the liquid in there and shake it around, and if you have a bottle brush, get it in there too.
When you're all done, drain out the water completely and let the soap scraps dry on a cloth or drying rack so you can use them again. Don't leave them sitting in water.