Strange, most of the CZ-52s out there are parkerized and were stored and shipped in cosmoline. This makes the nooks and crannies impregnated with grease and making it VERY rust resistant.Right. And then the first thing Joe or Jane Gunowner does when they get it home is hit it with brake cleaner to thoroughly degrease it.
I use Gunscrubber on newer guns like my M&P or 22/45 or stainless revolvers, but never on older parkerized pieces or old guns with a brown patina; in those cases, it's only the grease impregnated in the surface that prevents it from rusting away before your eyes like a cannon brought up off a shipwreck.
I've got some old, browned pistols that get handled a lot and taken to the range, and which have remarkably hardy finishes simply from getting wiped down with an oily rag regularly and not degreased. For old rifles that get left lying around, I like Butch's Gun Oil or Break Free Collector, both of which are pretty viscous and don't have any cleaners in them to evaporate; by this point, I'd bet the top layer of the metal on my flop-top Springfield is probably 50% ferrous oxide and 50% dinosaur juice.