Used glass jars are great and easy to reuse. Most people I know use their discarded jars for the storage of food products, such as sugar, coffee and lollies. Glass jars are also great to hold loose change in as well as random objects you may find laying around such as pens, buttons and batteries.
The resuse of glass jars is only limited by your imagination. Here are some more creative methods in upcycling glass jars.