I did not think about internal rust in the extractor, especially if a CCW gun looked great on the outside until I encountered a Ruger LC9s that had not been shot in at least year. It belonged to a friend of my son who joined us target practicing.
It would not chamber a round from the magazine. The outside looked new and clean. It turned out that the extractor, plunger, spring were froze solid by rust. I suspect exposure to sweat.
It was turned over to me to fix. I let the slide soak with penetrating oil in a zip lock bag for a couple of days. I checked out my sister's LC9s, read her gun's user manual. I watched a few YouTube videos on disassembling the LC9s extractor [j.i.c. I looked up LC9s extractor parts on Numrich Gun Parts site.]
[deleting the teal deer parts] It was an ordeal to get it back working. I got the extractor parts down to bare metal, cold blued, neutralized, then oil soaked. I cleaned out the extractor slot and spring tunnel in the slide. I reassembled with lotsa good oil. At home it feed and chambered a dummy 9mm cartridge. At the range I put ten rounds mixed make rounds through it, perfect feed and function.
Luckily the gun was not called on for SD with the extractor fused by rust.