u/anasarca1

I am planning to apply touch up paint to scratches and dings on my Corolla. There is one area approximately 1/4 inch in diameter where you can see bare metal underneath and than there is superficial rust overlying the metal. There is no rippling of the paint around the periphery of the bare metal, and it appears very localized. What type of prep do I need to do before I apply the touch up paint? Thank you in advance for feedback and advice.