Whisk flour and salt in large bowl. Whisk together milk and eggs in a medium bowl. Pour milk mixture into flour mixture, whisking to combine. Whisk in butter. Let rest for about half an hour. Add milk if needed.
Heat an 8 to 12-inch nonstick skillet over medium heat, and brush with butter. Pour 3 tablespoons or more batter into pan, tilting and turning skillet to coat bottom. Cook until top of crepe appears set, about 1 minute. Slip spatula under crepe and gently flip. Cook until bottom is firm, about 45 seconds. Repeat with remaining batter, brushing pan lightly with butter every 2 or 2 crepes. Layer over wax paper. (The first ones will not be your finest.) Makes about 24 crepes, depending on size.