[Picus]

The toothpick method + wetsand + polish is your best plan of attack outside a repaint. Honestly, I've done that method on something like 30 key marks this summer and I don't think the results will be perfect *however* since the car is black you do have an outside chance of acceptable results. The most important part is to be patient. When filling the scratch make sure you're *above* the level of existing paint (and remember, tough up paint will shrink), when you'tre confident the paint is above the level of the existing paint and is done shrinking start sanding. You want to sand until you can't feel the touchup anymore, if you've done this sort of work before it's not a big deal. If you haven't it can be a little stressful. When you're done polish out the sanding marks and hope for the best.

If you have any specific questions let me know.