Hidden corrosion?
To degrease or not, age old question.
Absolutely gosh darn right....age old question and hidden corrosion.....yeah, that sucks too..because it can and does exist.
I have several still in grease.. one, I have mentioned, the Cherrys imported Yugoslavian M48BO i bought. Cherrys had the goods back in the day, like Mitchells, only not molested, faked, restamped and worked over.. It's the bottom Mauser, and was slimy and grease covered when I bought it, I found the exterior was pristine, the bolt was in mint condition. The barrel had a pound of grease in it..so it was sealed......or so I though. I cleaned and cleaned.. Eventually the barrel started spitting out little 8mm shredded rusty rat nest patches... WTF. so upon further inspection, even though the barrel was packed with grease, the bore is really rough, enough to shred cloth patches.. Thankfully, it still shoots pretty decent....but, it's probably no where as good as it could be.
Now everyone claims the M48BO was a contract for export only rifle and are all like new..so did someone shoot it and pump it full of grease to sit for years, or did the grease fail to protect the metal. This much metal damage couldn't have been done here, as it came out of a sealed Cherrys box.
And no eyeballing my Vz.24