Mix the brown sugar, apple cider vinegar, water, mustard, cloves, cinnamon, and ginger in a small bowl.
Pour the mixture on top of the ham, making sure it covers it completely.
Put the lid on the slow cooker and cook on low for 6-8 hours until the ham is warm and soft.
From time to time, brush the ham with the juices from cooking.
After cooking, take out the ham from the slow cooker and allow it to sit for a few minutes.
Cut the ham into slices and serve it, pouring over the juices from cooking.