Hole punch, cut varying sized discs from 1200 1500 grit wet and dry. Attach these to erasers removed from the end of a pencil , stick the discs to the erasers with super glue, for precise/accurate keying of the chip.
Bar of soap... dip the prepared abrasive disc in a drop of water, then rub the disc on the bar of soap. Stops clogging?
Nicely keyed chip filled with a spot of primer, couple of applications, allow to dry thoroughly then flat this with the disc, before applying the colour coat level with the surrounding paintwork. When dry apply clear lacquer and when this has had a few days to harden then polish with a burnishing compound.
Never achieved a completely invisible repair with this method on horizontal panels, but it looks better than chips?
PS I use a sharpened cocktail stick or toothpick, lightly chewed at the sharp end
or sometimes an extra fine camel haired,(sable if you have one
: ) brush. It varies as to which I feel is the better choice of applicator.
: Have Fun.