In a nonstick skillet, cook sausage until well done and no pink remains. Drain. Put back on stove and add cheese, stir until melted. While sausage is cooking, beat eggs in a bowl with the evaporated milk. Salt and pepper as desired.
Pour eggs into the prepared sausage and cheese and cook until eggs are firm. Pour in a little of the salsa. Place fajita shells in a hot oven just for a couple of minutes to heat them up. Place in bowl with a towel over the top to keep warm.
Put the egg and sausage mixture in the tortillas and serve immediately. Add more salsa if desired. You can also serve with fresh chopped tomatoes or any of the above ingredients.