The best way to preserve ham with bone is to keep it in a dry place with enough ventilation and a stable temperature (never in the fridge), far away from extreme cold and hot temperatures and preferably hanged or in a Parmesan ham holder. When you cut ham this part is exposed to environmental action , this creates a oxidation that makes dark this surface, fat becomes yellowish and this can cause nasty smells. So it is necessary to protect the cut of the ham placing a slice of fat or bark (of previous cuts) in order to keep superficial fat  fresh and not resected, or covering the ham with a kitchen cloth.

The ham must be covered with a rag.

At the moment of preserving the ham it is necessary to cover the cut with pieces of fat or bark, or with kitchen cloth

It is recommended  to cut the quantity of ham that we think we are going to consume, in the opposite case there will be necessary to wrap it in transparent paper to avoid the contact with air.

If the ham that we want to preserve is boned,  we will have to introduce it  in a bag, vacuum  packed  and as it is consumed it will have to be kept in the hottest  part of the fridge and if it is possible cover it with a dry cotton kitchen cloth.