It is easy to see the difference between glass and paper and between paper and plastic. But how do you sort one kind of plastic from another? After all, they all look much the same.
Governments have come up with a set of numbers so that you can tell what kind of plastic something is made from. The numbers go from 1-7 and they are stamped into the plastic. They are usually placed somewhere out of the way, such as on the bottom of a bottle, so you may have to look hard to find them.
