Wash the pork shoulder under running water and dry well with paper towel. In a non metallic container squeeze the juice of all the lemons and mix with the sour orange juice. (If you cant find fresh sour oranges, can buy it in bottles or use regular orange juice mixed with equal parts of lemon) Using a wood mortar or garlic press, smash well all the garlic cloves.
Place the pork shoulder, skin down, in a non-metal container and pierce a few times with a knife. This will allow the marinating sauce to better penetrate the meat. Pour the lemon and sour orange mix over the meat making sure that some penetrates into the pierced holes. Pour the Worcestershire sauce in the same manner. Take the smashed garlic with you fingers and rub vigorously on all the surfaces of the pork shoulder. Push in a little garlic into the pierced holes. Cover with plastic wrap and let it stand in the refrigerator for one hour.
Preheat oven to 350°. Remove pork from the refrigerator and rub table salt vigorously, with your fingers, on all surfaces of the meat. (If you want great tasting pork, do not be shy with the salt!!).
Save the marinating sauce that has accumulated at the bottom of the container, this will be used to baste the meat, at least two times, while cooking. Loosely cover meat with aluminum foil. Cooking time will be approximately 4 hours, depending in the size of the shoulder and the characteristics of your oven. Cook for 2 1/2 hours and baste the pork with 1/2 the sauce that was saved. Cover again and let cook for another hour. Baste again with the rest of the sauce and this time, leave uncovered until done. Using a thermometer measure the inside temperature of the roast and keep cooking until it reaches 170 degrees. You may want to brown and toast a bit the surface of the meat by turning on your broiler burner for a few minutes before removing it from the oven. DO NOT LEAVE UNATTENDED WHILE USING YOUR BROILER. IT WILL BURN YOUR MEAT REALLY FAST.
For a real Cuban meal serve with Congri and Yucca.
Note: You may want to make some mojo sauce to be served at the table. Prepare it with the juice of 3 lemons, same quantity of sour orange juice, fresh onion slices, 1/4 teaspoon of salt and a drip of olive oil. Let stand for 1/2 hour. You may want to warm it up heat it before serving. but do not cook.
Save pork leftovers for Cuban or Pork Sandwiches !!!