A lovely coin in this condition.
I have one of these, but it ain't half as nice as this one

Made of iron. Iron much harder than bronze.
Most often, corrosion gets at these now, before wear did when they were issued.
You MUST keep this coin away from a moist atmosphere.
Keep it away from PVC album pages as well.
Mine HAS deteriorated a bit in the 30 or so years I have had it in my collection. (rust and darkening).
Air tight capsule OK, but you may have trouble getting the capsule in an album page, unless it is fairly thin.
Also consider to use a
glue sealed 2x2, and not a stapled one. It would also help to seal it in a home made holder made acrylic plastic sheet, recovered from food packaging or toy packaging.