I'm looking for some advice on an old acoustic that belonged to my great-grandmother. The guitar is likely from the early 1900's but there are no marks on it that would tell me what it is. I would like to get it into playable condition. At a minimum, I would need to replace the tuning machines and I did find some that should fit. My question is, how far should I go in this restoration? Tuning machines, nut, bridge? What about refinishing? It looks like someone (possibly my grandmother put a coat of varnish on the original finish. There's some left on the frets. Or would you leave it as?