You lose the patina by cleaning with soap or ammonia. Sometimes it's necessary to clean wood if gluing/patching is needed before reassembly, etc. I'd just rub it out very gently with 0000 steel wool saturated with raw linseed oilicon. Wipe it off and Bob's your Uncle. Forget the boiled linseed oilicon. Everyone that thinks raw linseed doesn't dry is just plain wrong. They just don't know how to apply it correctly.