Some of the older pellets would oxidize badly by forming a white powdery coating which may not be able to be totally prevented by simply controlling their storage environment.
IIRC, I've read that at some point, some companies started adding an ingredient to their lead pellet alloy to help prevent the oxidation from forming.
I'm not sure if the oxidation is found as often on old pellets that are stored in sealed tins or not.
IMO the white oxidation may act as a mild abrasive on the bore, but I can't say for sure.
It's probably not anything that folks would want to inhale if preventable.
I've seen buckshot loaded in old shotgun shells that were totally encrusted with the white powder residue which I refer to as oxidation.
I don't know what else to call it.
I wonder if that's one reason why some of the old Crosman pellets were coated with oil?
Is that correct that some of the Crosman's that were sold in the tins were oiled?
Anyone know more about any of the above?