Step 3: Second pass
Now that you have given your jar a good shake, quickly dump the water in the sink. Some of the rice should stay in the jar and that is good.
Refill your jar roughly half full with warm water. You do not need to add any rice or soap here. Now, repeat your shaking process to break loose any stubborn gunk in the corners.
If at this point your container is not quite as clean as you need it, you can certainly dump out the water and re-start the first pass. In my experience that is rarely needed though.