lol
i thought grinding it all off would be a good idea
seriously though like leonk said I had pretty much the same issue. small chip just around the edge of the rear passenger side window.
simply used a glass fibre pen to get the rust off, added some krust then just to make sure there was nothing else left. then used some etch primer with a toothpick to get an undercoat and once properly dried used the standard nissan touch up kit.
came out really well I thought.
If you've got anymore questions just drop me a line. was first time I'd done anything like this and it went well so I wouldn't worry to much. Most importantly I'd say be patient when your doing the work. dont rush it. A bit of good weather helps as well