"My mom made these delicious popcorn balls when I was growing up. While doing my Christmas candy and cookie baking, I came across her recipe. I made the family recipe for the first time this year. My daughters, grown with their own families, asked why I hadn't made these sooner. Thirty plus years later, this recipe will now be a family tradition at Christmas."
Sort through popcorn, discarding unpopped kernels.
Combine evaporated milk, sugar, corn syrup, margarine, and salt in a large saucepan over medium heat. Bring to a boil; stir constantly until caramel reaches 246 degrees F (119 degrees C) on a candy thermometer, about 5 minutes.
Pour some popcorn into a very large bowl. Pour in some of the caramel; stir until evenly coated. Add remaining popcorn and caramel in batches, stirring well after each addition.
Scoop some of the popcorn mixture onto a piece of plastic wrap. Gather and twist the plastic wrap to gently shape into a ball. Place popcorn ball on a baking sheet lined with parchment paper; repeat with remaining mixture. Let cool until set, about 15 minutes.