My only shotgun currently (an 870 express, short barrel) has no provision for chokes at present (and probably will not..). Whenever I'm doing any kind of work with threads that will be exposed to corrosive elements - it's always Nev'r Seize for me... Yes, it can be messy if you're over-doing it but long term I've never found any grease better for corrosion problems when you really need that fastener to come loose with a tool... years later. A few tips... I've learned to use thin elastic gloves when working with lubes, glues, or caulking that might stain (or just be difficult to remove when washing up after use), as well as keeping paper towels handy and promptly disposing of them immediately after use... I've had more than one clean up problem from epoxies, permanent sealing caulking, and stuff like Nev're Seize - caused solely by not cleaning up after myself -properly...
There are two kinds of Nev'r Seize - a copper formula for plumbers and an aluminum colored formula for general use. I use the general formula - and still have the original squeeze bottle that I purchase more than forty years ago now -but have to dip into it with a small screw driver as an applicator all these years later with the small amount remaining. Great stuff that allow you to dis-assemble something that's had hard use over many years -and absolutely no maintenance all -other than the original application... hope this helps...
