I'm not a mech guru. But doesn't that mean that, for long term vapocalypse planning, one should also then consider stocking up on that contact since essentially it is a consumable and, once damaged to a certain degree, will render the device useless until replaced?
I'm not a mech guru either, despite I have a nice (some would say
too nice...) collection. I'm just a guy with intermediate knowledge and a little bit of experience, but I did some reading up on several advanced topics such as arcing (and micro arcing, which is not the same thing as arcing...), and on what are the best strategies to avoid these problems. (And why.)
If two flat metal surfaces are pressed against each other flat, then tolerances in the machining and imperfections in the flatness and/or smoothness of the polished surfaces still ultimately limit the total surface area of those specific locations where no air gap occurs between them. Pressing the button disc in a slightly different spot causes the metal part to shift and/or tilt ever so slightly differently when it moves so as a result there will always be subtle variations happening in cohort with the imperfections. If you try to keep the contact surfaces as perfectly flat and smooth as possible the whole time, with each polishing session you will be removing a thin layer of metal always repeatedly until finally, the cumulated effect will be more similar to having poor tolerances in the machining so, excessive heavy polishing can be equally as bad as letting arcing marks grow worse over too long a period of time. Any copper firing pin worth its salt can be maintained with a pencil eraser to remove
just the high points─the tiny specks that are bumps on top of the surface that are caused by arcing damage. Ideally, this should be done a few times per day. As part of regular maintenance a sheet of 1000 grit sandpaper laying on a flat hard surface can also be used in addition to this, carefully gently, after you remove the firing pin. But the pits should not be removed, as removing them just takes away far too much metal like I said.
As for removing the high points on the bottom of the battery itself (or top of the battery, if the mech in question is designed such that the battery needs to be upside down, and uses the type of switch that isn't a constant contact switch) the best approach AFAIK is to use the Heavy Duty version of 3M Scotch Brite scouring pads specifically for this purpose. While it is true the fact a constant contact button is what can be used to eliminate this specific part of arcing damage before it happens, arcing damage still occurs inside the button nevertheless, so... proper maintenance is still going to be a thing to keep you busy.
That said, I think a bare solid copper firing pin should be able to last more than a lifetime. But that's assuming you didn't buy the type of mech that has severe arcing (yes... there are some real nasty mechs out there that are definitely not worth buying except maybe if they can still be fixed) and you aren't constantly neglecting the arcing marks so badly that more arcing marks pile up at a quasi exponentially accelerating rate, heavily on top of each other.
In any event, solid silver contacts in cohort with a well engineered firing mechanism is the easiest choice requiring almost zero effort to adequately maintain. It's a lazy solution... it works as perfectly as perfect gets, but then, I'm not overly obsessed with solid silver upgrades, or maybe only just a little bit obsessed...
