ive fixed those before. I detail and have had ppl bring me their car like this.
So what i am telling you here is not professional job, nor do i do this for living. So if your a DIY and wana save a few bucks....
get a 2000,2500,3000 paper. touch up paint, toothpicks, fold the 3k paper in half. Using the edge of it open up the scratch a tiny bit. Your going to need to fill up the entire key with paint, using the tooth pick. Use the pick to make sure its even, and it gets all the way down and filled up.
your going to have to do this like your painting a car. fill it, let it dry for 3-4hrs. go back and try to fill in more. Sooner or later it will be filled in and the extra will cause a slight bump/ridge/etc.
than let the car sit over night. come back with the 2k paper, sand down so it is flat. 2500k paper, than 3k paper....
you should be able to polish out the rest with a porter cable or flex, etc
if you look on you tube you should be able to find a vid of this. which should really help.
I also know i didnt do the best job explaining things here as well.