Rinse beans. In a large saucepan, combine beans and 3 cups of the water. Bring to boiling; reduce heat. Simmer for 2 minutes. Remove from heat. Cover and let stand for 1 hour. Drain beans and return to saucepan.
Add the remaining 3 cups water, ham hocks and butter to beans. Bring to boiling; reduce heat. Cover and simmer for 1-1/2 to 2 hours or until beans are tender, adding more water, if necessary, and stirring occasionally.
Remove ham hocks; cool slightly. Remove meat from ham hocks; chop meat. Stir chopped meat and salt into beans. Cover and cook for 5 to 10 minutes more or until heated through. Makes 4 to 6 servings.