Combine garlic salt, chili powder, dried oregano, dried basil, cumin, ground coriander, brown sugar, and sweet paprika.
Rub the spice mixture evenly over the pork. Place pork in the bottom of a slow cooker (minimum of 6 quarts)*
Squeeze the juice from the oranges and limes over the pork. Place rinds pulp side down in slow cooker over the meat.
Cover and cook on low for 10-12 hours, or until pork is tender and falling off the bone. Use a fork to pull away from bone and discard it.
Preheat oven broiler. Line a half sheet pan with parchment paper and arrange pork in a single layer. Place underneath broiler until tips of pork are browned and slightly crisp, about 3-5 minutes. (Don’t walk away from it. Keep an eye on meat to make sure it doesn’t burn or become overly browned).
Serve finished pork in corn/flour tortillas, or over rice.
** Keep in mind that you need to trim your pork so that it fits in your slow cooker... I cut mine in half to end up with a 3.5 lb cut of meat (and I froze the other half)