Despite having owned shotguns for the majority of my life, I recently ran into a new problem. A choke tube became stuck in my Stoeger M2000. To be honest, I noticed it about two years ago, but this shotgun has basically become my loaner if someone needs to borrow one, and the offending choke was a modified (the jack of all trades), so I didn't really care. Thinking of taking it on an upcoming bird hunt I decided to remedy the situation on the principle of the matter.
My first tactic was to hose it down with PB Blaster. I have used it on various automotive tasks and it does well, and its cheap. The problem being, there isn't much tolerance for this stuff to seep into. I'm sure I could have let it soak overnight and gotten better results, but I'm not always that patient. The next tactic was to apply heat. A hairdryer might work, but a dedicated heat gun is better. The key is to heat the barrel, not the choke at the same time.
Ok, so that didn't work exactly as planned. Yes, that is a bent and mangled factory choke tube wrench. As much as I would love to claim super human strength, I think we can chalk this up to inferior metallurgy. Not to mention my entire household just got done being ravaged by the Noro Virus, I was in no condition to give it 110%. But, as you can see, the tube eventually broke free after several heat cycles.
What you see is some obvious corrosion on the choke body, not the threads. What you don't see is any trace of the penetrating oil. It was worth a try, but in this case heat won the day. Everything looks to be in good enough shape to reuse, except the choke wrench...
I have started using Slide Glide - Lite grease on everything firearms related. It seems to do well as a choke tube lubricant as well. I never used to lube my chokes, but this situation made me a believer. In hind sight I think I was over tightening chokes. Don't do that. A benefit to extended chokes is that you can perpetually hand check them for tightness and you have some options if one should become stuck. I doubt I'll use flush mount tubes again unless I'm forced to, but you can guarantee anything I use will be well greased.