Place the meat in a large roasting pan, pour on the vinegar and sprinkle the salt, and rub it all over the meat. Let it sit as you prepare the marinade.
Heat a comal or small skillet over medium-low heat. Toast the dried chiles for a minute per side, or until lightly toasted. Place in a saucepan along with the garlic and cover with 4 cups of water. Bring to a boil over medium-high heat, then lower heat to medium and simmer for 10 minutes until the chiles have softened and plumped up.
Using a slotted spoon, transfer the chiles and garlic to the jar of a blender, along with the 4 cups of cooking liquid and the oregano, cumin, nutmeg, black pepper, and cloves and puree until smooth. Cool to room temperature.
Cover the meat with the adobo, making sure it is all well rubbed. Cover and let sit in the refrigerator, ideally, anywhere from 24 to 48 hours (or at least 2 hours).
Remove the meat from the refrigerator. Preheat the oven to 375℉.
Place the meat and all of the marinade in a roasting pan, tightly cover with aluminum foil, and roast in the oven for 2½ to 3 hours. Uncover and continue roasting for another 35 minutes, or until the meat is so tender it is falling off the bones and it is browned on the top. Taste the broth and adjust the salt. You may need to add some water to the pan if it has reduced too much during the cooking.
When it comes to serving, you have many choices: You can transfer the meat to a platter, moisten with the remaining broth, and assemble the meat in tacos or make birria-dillas (or quesa-birrias). You can garnish the tacos or quesadillas with the onion, cilantro, lime and salsita of your choice, such as the tapatía.
Credit Pati Jinich