This may well be an obsessive-compulsive's problem, but...
...to no one's surprise, California's smog reduction program won't pay you to take an old Prius off the road, so we're going to donate the car. GothBard suggested the Berkeley Humane Society, and they have a handy-dandy, "Fill in this form and we'll pick up your car," form...
...except...
...the critical question of WHEN isn't mentioned.