Pull husks up to cover the corn ears and place the corn in a large bowl or pot. Cover with cold water and place a large plate or other weight on top of the corn so that it remains submerged. Allow the corn to soak for at least 1 hour.
In a small bowl combine the sour cream and milk and set aside.
While the corn is soaking, prepare a grill or barbecue to medium-high. Adjust the grilling rack so that it sits about 4 inches away from the fire.
Lay the corn on the grill and cook for 20 to 25 minutes, turning frequently. Remove and allow to cool slightly.
Preheat the oven to 250 degrees F.
Pull the husks back to form a handle and brush the ears evenly with the melted butter. Squeeze the lime halves evenly over the ears of corn, and brush the ears with some of the sour cream mixture. Sprinkle the cheese evenly among the corn ears, coating on all sides. Sprinkle the ears evenly with the chili powder and kosher salt. Place corn in a baking dish and put in the oven for at least 5 minutes, or until ready to serve.
