As time goes on, more and more smartphone is being created and introduce to people. Surely we have some old smartphone that is fell into disuse and being kept in drawer. Then how are we going to do with the old smartphone? If we think creatively, the old smartphones can be used in daily life, which can be considered turning waste into treasure. 1. Car Navigation Systems. If you have any smartphone that have 3.5 inch screen, and have GPS function, you can bought a phone handle and prepare power source for the old smartphones to become a Car Navigators. There are many free navigators app like Waze and Google Maps. 2. Driving recorder. Some driving recorder apps can be installed into the smartphones so that the phone can record whole scene when you are driving. If any accident occur, you can use it as a prove to prevent from being wronged. 3. Family Monitor 4. Universal Remote Control 5. File Scanner Cam Scanner, or Doc Scan can be installed in your old smartphones.