So, I have a few experiences with this type of thing. I'm going to try and pool them all together, but don't have any solid pictures of any of them
It can be fixed with touchup paint, sandpaper, and polish. It takes work, but I have seen a 100% repair made this way.
When we get to working on my brother's Mustang, I will make a detailed how-to. But for now, here goes:
1. clean the scratch/chip really good.
2. Prime if bare metal is showing. Let dry
3. Use your choice of paint brush or toothpick to get the basecoat in the scratch. Note: many people say to only get the paint in the scratch. This isn't the only way to do it. You can just use the brush and smear the paint all over the cut and the surrounding paint.
4. When the paint starts to get close to the top and is dry, but BEFORE IT GETS LEVEL, you need to wet sand w/ 2000 grit. All you should sand off is the touchup paint that is not in the scratch (ie. on top of the facroty clearcoat). Then pile on the clear coat until it is a bit ABOVE the exsisting clear coat.
5. Again, use very little pressure when you wet sand w/ 1500-2000 grit sand paper until it is smooth. Tip: using a water solution with a bit of soap will speed up the sanding process.
6. Wet sand all area w/ 3000 grit
This has worked for a 100% fix on my friends black camaro. It might show a bit more on lighter cars. Silver seems especially hard to get right.
Never worked with this, but it looks like a promising way to fix chips and scratches w/o sanding: www.drcolorchip.com