Paint pen or canned paint?

Hello, would have a short question. Have with me at the mopped frame several small places, where the varnish has burst off or even smaller abrasions are present. It is a Virago XV 535. The frame is black, but I do not know if is Unilack or 2K, I don’t know about it. Now I had thought, since there are places, which you don’t see anyway, I could buy a black varnish pen and then with a fine brush or a toothpick, depending on the place then the P that I wanted to ask if you could just use normal paint from such a small mini can.They are cheaper from a price point of view and you have more content. Do you actually need to brush it over for each spot in addition to clear paint? Should you grind each spot with a 600 paper or would you rather go over it with a wire brush? Thank you