I'm going to see about getting one of those bags too. Thanks for the idea!
And if you want to save soap slivers and put them to use, you can gather them all in one of those plastic mesh bags that some tomatoes and other types of produce come in, tie it up, and use the bag of soap slivers to clean the ring out of your bathtub after you use it.
If you take showers, I don't know what you'd use it for, but surely you can think of something...
Getting off my soapbox now.