When you’re at the point of soap slivers or the last few crumbly bits of a shampoo bar, pop the remnants into your soap saver bag. Apply water and massage product inside the bag to work up a lather. Massage onto your body or head as usual. When you are finished, give it a quick rinse and just hang it up to dry.
If you are travelling or do not have access to an adequate soap dish with drainage, you can also store full size bars of soap or shampoo in a soap saver bag.