In heavy saucepan mix sugar, corn syrup, cream, and salt. Bring to boil and cook to soft-ball stage. Slowly, so boiling doesn't stop, add evaporated milk and butter. Continue cooking till about 238 degrees F. (247 degrees F. at sea level). Arrange pecans in clusters on wax paper on baking sheet. Drop spoonful of caramel onto each pecan cluster. Cool. Dip candies in chocolate, if desired. Makes 2 1/2 pounds of candy.