Need advice on cleaning/oiling/preserving inherited guns

[Jake]

I recently inherited these and would like to clean them up, eventually and hopefully shoot the luger but right now my main concern is preserving them for lack of better words. I own a few modern firearms and use stuff like rem oil wipes, hoppes, clp, etc. but I don't want to do anything to mess them up. Also the wood grips and leather holster, anything I should do to them? Thanks in advance!