Nitrocellulose lacquer can be repaired a couple of different ways; it is one of the reasons that many people favour lacquer over the newer poly (-urethane,-ester) that cannot be repaired without either leaving witness lines or having an expensive set up. New lacquer can be brushed on, and it will "melt" (re-amalgamate is the formal term) with the old, and after some polishing, will look just like the existing lacquer, and will in fact, be one with the old lacquer. The other way is to use Quala-Renew, which is just the solvent part of lacquer, and will pretty much do the same thing. Difference is that the Quala-Renew doesn't have any of the solids that lacquer does.