Combine the annatto seeds, cumin seeds, oregano, allspice berries, and salt in a spice mill or coffee grinder. Grind to a powderlike consistency. In a small bowl, mix the powder with the garlic and lime juice. Store in an airtight container, in the refrigerator.
Use for Cochinita Pibil or any grilled seafood. Yield: about 1/2 cup