I carried blued handguns, almost exclusively revolvers, as a young man. There were virtually no stainless steel models back then and the cost for one of the few custom finishes (such as Armaloy) then available was essentially equal to buying another gun.
We used silicone auto waxes to help protect our carry and hunting firearms from moisture and corrosion. It worked very nicely, and pretty much eliminated the need for daily inspection and maintenance chores.
As was stated, we learned to avoid any product with the words "cleaner" or "polish" on the container. These were automotive products and those words usually indicated that the formula included an abrasive, a chemical solvent or both. For the most part these would seriously degrade or even destroy a blued finish.
Two modern products I use and can recommend are "Renaissance Wax" and Blue Wonder's "Armadillo". The former is a proprietary blend of "hard" natural waxes and an old standby among museums and serious collectors for valuable artifacts to protect then from degradation while on display or in long-term storage. The latter is a relatively recent firearms-specific polymer product.
While they won't eliminate "holster" wear, they do seem to slow it down significantly and offer much more complete and longer lasting protection from the corrosive effects of moisture, environmental salts and acids and the like than oils or greases.
