Question re: Rust outside my barrel

[Juna]

So I was cleaning my gun the other day after a range session, and I noticed that there is what appears to be a rusty fingerprint developing on the exterior surface of the barrel. I always lube the barrel, inside and out, after every range session (after cleaning it, of course), so I'm not sure how that happened. This time I took great care to make sure that my fingers never touched any of the internal parts after I lightly lubricated them and reassembled the gun.

So I have two questions:

1) Is there anything I can do to remove the rusty fingerprint?
2) Will it cause any harm or prevent further spread of rust if I just do nothing about the rust and keep cleaning and lubing as I've always done?

Thanks in advance

 

[gudel]

soak it in break free clp, scrub tomorrow.

what gun is it?

 

[mete]

Some gun oil and 0000 steel wool. Is it your fingerprint ? I ask that because there are some people whose oils in their fingers are very corrosive. This can rust steel even when coated with preservative oil !!!

 

[Juna]

It's my CZ 75 BD. I'm not sure if it's my fingerprint, but I assume so since I didn't notice the fingerprint last time I cleaned it. It's odd, though, b/c I'm pretty meticulous about cleaning it and oiling it. I assume I would have noticed the mark before if it had already been there. I did buy the gun used, but barely used. Nobody but me has touched the outside of my barrel since I bought it.

The entire gun is steel, and there are no other spots of rust that I can find. I handle it all the time, so I would think if my fingerprints were that corrosive that I'd be rusting out the grip, slide, etc. I'm not even sure it's rust, but it's a dark brownish discolored area in the shape of a fingerprint on the outside of the barrel.

 

[Juna]

Thanks for the suggestions, all.