nancy's popcorn balls

1 pkg brown sugar
1 cup light corn syrup
1 cube butter
1 can sweetened condensed milk
3 gallons popped corn

combine brown sugar and corn syrup and cook, stirring constantly until mixture comes to a boil. Add butter and continue cooking until butter melts and mixture boils.
Add sweetened condensed milk and bring again to a boil, then cook over medium heat, stirring constantly until mixture forms a soft ball when tested in water.
Pour over popped corn and stir until syrup is evenly distributed. Spread out thinly on waxed paper or let stand a few minutes and shape into balls. Makes 3 dozen.