My travel guitar has developed a horrid buzz when I play my bass E (6th) string at the fifth fret. This pushes the string down too close to the sixth fret. I know nothing about guitar repair, but is it possible to simply file down the sixth fret? Should I acquire a fret file or is there something less costly? Do I need to know what I'm doing? It's not an expensive guitar but I don't want to damage it. (I'd never try this with my Martin. On the other hand, my Martin would never develop such a problem.) I could return the travel guitar for repair, it's still under warranty, but shipping it would cost almost as much as a fret file.