Yes Jim, the exposure theroy is in some way part of my argument... an object kept still for decades in the same position, will suffer different range of oxidation, dust and rust, depending on the sides exposed. Sure, it sound really appropriate.
There is also another thing to consider.. most of the well preserved items we can see today, weapons, armors and so on... kept their overall good conditions expecially thanks to the fact that they were "family collections". So they came out from quite "protected" situations... on the contrary, many corroded items were found in outdoor enviroments, such as graves, battleflieds and so on.
This is a situation we can see even on most recent items such WW2 helmets, bayonettes and others.
The hardening of late medieval weapons and armors is for sure a good point for the preservation, but i think that the main ruining process is caused by the real place where the items were left for centuries.
Note: once an expert told me that technically there is no "iron items" (speaking about medieval times) but they are all different level of steel... thats because the iron is in fact the mineral itself
