These can be utilized for making some new creative form of parks, gardens. So along with entertainment, environment problem like solid waste disposal can be solved. These parks can be the initiative for creative work.
They can also used in creating museum. This would show the future generation of the past cars. They can see to themselves how the automobiles have developed and much more. Its all how we represent them. If we dump them, it becomes waste and the same thing if we present it quite different way which all like to see. it would surely welcomed and encouraged.
By doing such creative things, we can make the best possible use of them.
If it cant be used for such purpose, we can go for the better way like using its various parts as scrap, recycling them instead of using the fresh raw materials again and again. So raw materials can be conserved at the same time, the energy required to process such scrap will be some what less as compared to the fresh feed.
So don't waste the resources we have, utilize them to the best possible way. This can help to save our earth & natural resources.