James,If CLP runs to where it can wick onto O-rings, the solvent (cleaner) tends to cause them to perish and leak air. Wiping down with a cloth that has oil on it should minimize the risk.I thought the Marauder parts were anodized and painted. If you mean the outside of the actual steel barrel, wiping that down with almost any oil or grease, to act as a moisture barrier should work.If you are seeing rust on the outside of the barrel, then perhaps the bore is also at risk. People shooting lubed projectiles probably have the lowest risk. One might argue that a thin layer of lead seals off the bore from moisture. I am not so sure this is an unbroken layer. Unless slight rusting encourages lead to smear off there, thereby shielding the previously "unplated" sections with their own lead layer....I apply a thin film of oil to my barrel bores to act as a barrier, unless I am planning to shoot the same airgun again the next day. This may be overkill, but I don't want to see rust in a barrel...
Therefore, I was looking into what members used in order to keep the rust at bay. I've picked up some Ballistol wipes off amazon (3xpacks for $13) as they seem to be what other recommend it use.When you pay a lot for your rifles or any gun, you want to do what ever you need too in order to keep them clean