Preserving Zincolns

I dip in acetone and blot dry before storing in whatever method you use.

The key is low humidity. I would take Maineman's suggestion of an aceone rinse and let it dry (should dry in just a few seconds) then store it in an relatively small airtight cointainer with a silica gel packet. This creates a micro environment where the silica can absorb most of the moisture from the air and the airtight container prevents anymore moisture from getting in. The corrosion process is an oxidation-reduction reaction and it requires oxygen AND water to proceed. Eliminating the oxygen is difficult but elimiating the water is easy.

Yea, acetone rinse, put it in an airtite holder, put that in a ziplock with a desiccant pack and then put the bag into a tupperware type container. It will be good for serveral hundred years like that.

scurry64, that's not a joke,it actually happened to justcarl

The manufacturer is not really relevant and in many cases, one company will make the acetone while another markets it for commercial use. Just do not use nail polish remover that contains acetone. Everything that is commercially available as acetone should be pure enough for conservation but always perform an evaporation test on a new lot before use. Pour a small amount in a glass dish and let it evaporate. It is fine to use as long as the glass is clear after evaporation and no residue is left.

Maybe, oxidation is impossible to stop altogether. I don't think it will be a drastic darkening, just slight as the cuprous oxide layer thickens. Once the layer is thick enough and assuming the coin is well protected from air using the above method, it will remain in that state virtually forever IMO. Cu2O forms a pretty good protective layer and there's no reason for the reaction to move to the formation of curpric oxide unless fairly strong environmental effects get to the coin.

What do YOU say about that?

Anything is possible pending on what is done or not done with whatever is used. For example it was stated to put them in a Tupperware container. Which type was not stipulated. The Fridge Smart type has holes in it for air ventilations. The Stuffables have flexible lids that move up and down pending the temperature also making them not air tight. The Flat Outs expand and contract and too and are not air tight.
Then if the Zip Lock did not have the excess air pushed out prior to sealing, could have humidity, miscellaneous gasses in there already.
Looks like the air tight might save the day here.