1. Soak peanuts in water to cover in a large stock pot at least 8 hours or up to 24 hours. (You may need to weigh down peanuts with a large plate or lid to ensure that they are fully submerged.) Drain and rinse.
2. Place peanuts and desired amount of salt in stock pot with 4 1/2 qt. water; bring to a boil over high heat. Cover, reduce heat to medium-low, and cook 6 hours or until peanuts are tender, adding water as needed to keep peanuts covered; stir occasionally.
3. Remove from heat; let stand 1 hour.
Cajun Boiled Peanuts: Proceed with Step 1, adding 1/2 cup Cajun seasoning to water. Proceed with Step 2, using 1/2 cup salt and 5 to 7 Tbsp. liquid Cajun crab boil before bringing to a boil. Proceed with recipe as directed.
Ham-Flavored Boiled Peanuts: Proceed with Step 1. Omit Step 2, and bring 6 qt. water and 2 smoked ham hocks to a boil in a large stock pot. Reduce heat, and simmer 3 hours. Remove and discard ham hocks. Cool broth; chill 8 hours. Skim fat from broth. Add peanuts and 1/2 cup salt to broth. Bring to a boil over high heat. Cover, reduce heat, and cook 6 hours or until tender, adding water as needed to keep peanuts covered; stir occasionally. Remove from heat; let stand 1 hour.