I often use cotton buds for touching up paint, I'm always lifting them out of the bathroom and taking them out to the garage then she'll come out and give me a row - I had 3 tubs of them out there once and none left in the house.
I also bought a great touch up kit from Halfords for a silver metallic Volkswagen, it comes with the three bottles, base primer, colour coat and clear coat varnish. All the bottles have their own brush and they're very fine - just the job for tiny little spots. Either that or get some of Toulouse Latrec's single hair brushes harvested from young camels in the Ghobi desert.
2015 Antara Exclusiv 2.2 163ps Manual 2WD