I recently bought (the previous owner was about to throw it out) a Lauberger & Gloss baby grand piano (from 1903 according to the serial number) which has been reconditioned in the 80's using techniques which resulted in questionable results (see for example: paint spraying on the shellac without dusting or repairing the surface, restringing without replacing the torn felt under them etc.).
I bought it with the intention of saving it from the dump and serving as a decorative element in a holiday home but then I thought that it would be nice to improve its condition or even manage it to be playable. I tried to search a technician, but I couldn't find one in our region so I decided to do what I'm able to myself, because I have nothing to lose at this point.
The first thing was (after a thorough cleaning and polishing) the replacement of the damper felt, regulate the damper mechanism and regulate the action. I did it according to various workshop manuals and now it feels surprisingly good compared to the original state. It also sounds good (considered to its condition) even without voicing or tuning, which I clearly can't do myself. I saw some groves on the keybed caused by improper screw length used to attach the action stack. Other than that, as somebody sprayed the rim earlier during the mentioned renovation, they painted a section of the keybed as well which resulted in an improper function of the una corta mechanism.
I cant find any information about the keybed (and a small part of the rim interior, which flows with the keybed upwards, highlighted in the attached picture), especially if they are meant to be unfinished, just the raw wood or are they normally treated with something (#1)? I'm 90% sure that it has to be just the raw wood (and momentarily dirt on top of that) and if that's the case, sanding with a fine (finishing with 800 Grit) sandpaper in order to reduce the friction between the action and the keybed considered as an acceptable procedure (#2)? Also is it safe to use wood protector against insects (in Hungary there is a wood preservatives, called Xylamon) on the raw surface for preventive purposes (#3)?
I have a question about lubrication. I read that for the keypins, Teflon can be used to reduce friction. But what about joints in the action, the backcheck and the knuckle (#4)? I've read so many variants that I feel like better asking somebody who has experience with that.
There is some residue on the cast iron plate between the tuning pins (I know it's not a good sign). Is there a proper way to clean it, or should I do it with some alcohol and cotton swabs to avoid getting something in the pinblock (#5)?
The piano has original ivory keytops but some of them have yellow markings. They are not homogeneous yellow, more like patterns, like liquid splashes. I've treated them with some milk and rubbing, although it helped something it's not that huge difference, maybe it's just cleaner. Buffing them (slowly and carefully) with some white rouge would help to remove these markings or are they normally deeper than that (considering that it caused by liquid) (#6)?
I'm grateful for any advices even if it answers one of the issues!
(I apologize for the grammatical errors, I'm not a native English speaker)