Remove husk from the tomatillos and rinse off all of the sticky residue. Fill a small saucepan a quarter of the way with water and add the chilis, tomatillos, bay leaves, and whole cloves. Bring to a boil over medium heat and then reduce to a simmer. Once the tomatillos have turned yellowish, remove the pan from the heat and set aside. Be sure to reserve the liquid.
In a molcajete (lava rock mortar and pestle found at Mexican grocers) or the cup of a blender or processor, mash (blend) garlic and salt to a paste.
Add a couple of chilis and mash or blend those with the garlic paste. Add four tomatillos and mash or blend until chunky. At this point, taste for salt and tartness. If too tart, add another chili. If too spicy, add more tomatillo. If too thick, add the water from the tomatillos a little at a time until desired thickness is achieved. Add chopped cilantro and onion, if desired.