For an added touch, you can cover the can with red saran wrap to make people think you're going backwards.
Just kidding, don't do that. Safety first, kids.
~Not-"Not-So-Handy Andy" Jack
That's right, Prius owners: if you were REALLY committed to conserving and helping the environment, you'd get rid of that costly and resource-consuming sheet metal and switch entirely to plastic wrap.
...when you can just cover them up?