Put 3 quarts of popped corn in a large grocery sack.
In a 2-quart bowl, put: 1 c. brown sugar 1/4 c. white Karo syrup 1/2 tsp. salt
Microwave on high for 1 minute periods, stirring after each minute until melted. The boil for 2 1/2 minutes on high. Then add 1/2 teaspoon baking soda; stir well, it will foam up.
Pour caramel syrup over popped corn (in bag). Shake it up. Close up sack and microwave 1 1/2 minutes on high. Take out and shake. Put back in for 1 minute on high. Spread on cookie sheet and let cool. Then break up into pieces.