I just picked up an absolutely pristine Brno ZG47 in 30-06. This rifle looks like is was simply built then stashed away in a vault for 57 years. Breech area is full of a dried substance like cosmoline and the bolt has dried wax on and in it as well. However, the safety is stiff as hell and I have worked a ZG safety before and it should not be stiff, but butter smooth. Any ideas how to smooth the safety engagement/disengagement? I can take the firing pin out of the bolt body, but beyond that, I am stuck. Thanks for any help.