Measure the bacon grease into a 6 quart pot and place over high heat. Add one or two popcorn kernels as testers. When the test kernels pop, add the rest of the popcorn and cover with a lid. As the popcorn starts to pop, shake the pan back and forth constantly to keep the unpopped kernels on the bottom where they can pop. When the popping slows down, remove the pan from the heat and let it finish popping.
Pour the popcorn into a large bowl or paper sack. Season with half of the seasoned salt and stir. Taste before adding more salt if desired. Toss with bacon bits and shredded Cheddar cheese for an extra special treat. Store leftovers in lunch sacks or sandwich bags.