What is this brownish residue coming off my P30's slide?

[kerplode]

I picked up a P30 in 9mm a couple months back, but due to life and work I didn't get around to cleaning it and prepping it for test firing until this weekend.

Anyway, I was wiping the slide down with Corrosion-X and I noticed that the patches were coming off a darkish rust brown color. I'm pretty sure this stuff isn't corrosion, since AFAIK, HK's HE finish is more or less a ferritic nitrocarburizing process similar to Tennifer. What could it be, though? Some sort of preservative? Maybe something coming off the "bluing" or whatever that final finish over the HE is?

Not really worried about it, just curious if anyone knows what it might be.

[Slvr Surfr]

Could it be like Glock's anti-seize compound ? I would highly doubt it should be anything to worry about, regardless.

[spr1]

I would imagine it is the rust preventative grease that is also all over the inside. I would give it a good cleaning inside and out with Slip EWL or something decent and shoot the heck out of it.
Ps. I have never used Corrosion- X, so that might be good as well.

[F-Trooper05]

Sounds like you're describing the packing grease.

[kerplode]

Just for shits, I sent an email to HK customer service to ask them about the brown goo. They confirmed that it is the packing grease they apply prior to shipping.

So, mystery solved and my curiosity has been fulfilled. :-)

Thanks!

[JonInWA]

I'm sorry, I just can't resist: Did you wash your hands after you flushed?

Ok, I'll go back to the 5th grade now...

Best, Jon