Healing Objects

I recently scratched my car while driving it out of the garage. It felt bad, because I know there is no way to ever revert it to its original condition. Those scratches will be there forever--too small to justify expensive body work, but big enough to be noticeable.

It's the 21st century. Where are the healing materials? When I cut my finger, I don't give it too much thought, knowing the cut will heal in a matter of days, leaving no traces behind. If I break a leg, that's a different story. The bone will heal too, but not without proper treatment.

Similarly, there are many mechanical components of a car that will always require replacement or repair, but it seems to me that we already have the technology to coat vehicles in healing materials:

http://www2.rnw.nl/rnw/en/features/science/050801rf?view=Standard

Where are these cars? I want one!