There is a commercially available product called Langka that "repairs" chips. http://www.langka.com/

I have had only moderately good results with it. It is a petroleum distillate that softens partially cured touch-up paint, which then allows you to "shave" off the extraneous paint from around the chip by rubbing it with a hard flat surface covered with a finely woven cloth.

The problem I have experienced with it is that it seems to discolor the touch-up paint that is left behind in the chip, and you never can actually get the paint in the chip to fill up to exactly the right height. I am still trying to figure out if this product can really work as good as they say it does. I have been experimenting with cure times and rubbing methods.

I don't think that Langka would fix the chips below the gas tank door; they are on a curved surface...but a non-metallic paint like white probably has the best chance to work.