Paint chip is rusting

bullet1

I'm still confused as to how you can get and agitate sand paper enough to get into a lower surface area the size of a small chip. Whether or not you want to slope off the edges or not, actually getting into the chip enough to get rust out like that with paper to me sounds like it would be terribly difficult. Especially without damaging and scuffing up the paint around it. Granted I don't work with sand paper much, but I've done a little.