I'm in the process of restoring a bunch of double hung windows from the 1920's. Some of the windows aren't painted on the inside and have a clear finish - not sure what it is. Parts of the wood still have a good coating, while other sections don't have much and have turned a darker color. Not really sure how to best approach this. Any recommendations on how to restore this finish?
See the photos for more details
See the photos for more details
