I've never had one myself, so my experience is limited, but here is one suggestion from the web:
Marinate in butttermilk for five days, then wash off in cold water and saute in butter, garlic salt, pepper and accent. If necessary, slice into small pieces, preferably prior to marinating
Marinate in the same way and make into a stew. Brown first, then cook in wine or sherry with some celery, carrots, onions and small pieces of ham. Remove vegetables, blend, then add back to thicken the cooking solution. Use salt, pepper and garlic as requited. Also, a tbsp of sugar
Grind in a food processor. Add bacon fat, oregano, sage, garlic, sugar, salt, pepper, accent and mix into a sausage
Plain yogurt would also have a similar effect in tenderizing like buttermilk since it is only mildly acidic. You could construct a marinade using either buttermilk or yogurt and give it some time in there.