Remove the ham from packaging and discard any glaze packet if not using
Trim the ham if needed so it fits in the slow cooker
Place the ham cut-side down in the slow cooker
Add 1/2 to 1 cup of water, broth, apple juice, or pineapple juice to the bottom
Cover and cook on low for 3 to 5 hours, or until heated through
Check the internal temperature; it should reach 140°F if fully cooked ham, or 165°F if reheating leftovers
Spoon juices over the ham occasionally if desired
Add glaze during the last 20 to 30 minutes if using
Let the ham rest for 10 to 15 minutes before slicing
Slice and serve