Spray the inside of a 6-quart crockpot with cooking spray.
Remove the inner skin (membrane) from the ribs and place them in the crockpot.
In a small mixing bowl, combine the barbecue sauce, brown sugar, minced garlic, Worcestershire sauce, and cayenne pepper (if using). Mix well.
Pour half of the sauce mixture over the ribs, ensuring they are completely covered. Season with salt.
Cover the crockpot with the lid and cook on low for 7-9 hours or on high for 3-5 hours.
Once the ribs are tender and falling apart, transfer them onto an oven tray lined with parchment paper.
Pour half of the juices from the crockpot into the remaining sauce mixture and mix well.
Baste the ribs with half of the sauce mixture and broil in a preheated oven at 400°F (220°C) for about 10 minutes, or until the edges begin to char and crisp.
Serve the ribs with the remaining sauce.