Smear the bacon grease on the bottom of a large slow cooker. Cut the pork into large chunks and place inside the slow cooker. Then add ALL remaining ingredients around the pork.
Turn the slow cooker on: Low for 8-10 hours, or High for 4-6 hours. Once the pork is fork-tender, use 2 forks to shred the meat into the juices.
If you like your carnitas crispy on the edges (like it's served in restaurants) use a slotted spoon to scoop the meat out of the juices and spread in a thin layer on a baking sheet(s). Place on the upper oven rack and broil for 2-5 minutes, until darker crispy edges form. Do not take your eyes off the broiler, you can burn the carnitas quickly. Serve over rice, taco, or on top of salads!