Reusing
Reusing is taking a material or an object with one use and changing it into an object with a different use.
An example would be to take an empty cereal box, which is made from boxboard, and make it into a cubic decimeter.
The advantage is that when the project does not have any furthur use, you can recycle it. You will save money, learn a lot and it is great for the environment!
This student reused old cd's to make wheels for his gravity car.