Bars of soap are great because you don't have to fill your house with any unnecessary containers, but when your bar becomes a nub it's pretty useless -- but you don't have to waste it. Here's a handy technique from eco-friendly home blog Re-Nest that'll help you combine your old nub with a new bar easily and ensure it stays that way.
Photo by Desi
The trick is to use your fingernail, a paperclip, or something else that's small and has the ability to cut soap, and create several parallel notches. You'll need to do this on both the new bar and the old nub. (This will create soap shavings, but you'll want to save those because they can make the combining process easier.) Once you've notched both pieces, fill the grooves in the new bar of soap with a little water. Now match up the scratches you made and press them together, applying even pressure. (You can also create a paste with the soap shavings and use some of those as well if you're having trouble.) Leave the bar overnight and it should be ready in the morning. No more wasted soap!