Begin by rinsing your peanuts thoroughly by adding them into a strainer and running cool water over them. 

Once the peanuts are rinsed well, place them into a large stock pot and add your seasonings including: the salt, cajun seasoning, Old Bay seasoning, crushed red pepper flakes, brown sugar, liquid smoke, and garlic powder.

Now add enough water to the pot to cover the peanuts completely. Stir the seasonings into the water. 

Add the pot to the stove and bring it to a boil over medium-high heat. Once it comes to a boil, reduce the heat to low and add a lid to the pot. Leave the lid cracked a bit so that the steam can come out of the pot.

Let the peanuts simmer over low heat for about 7 hours. Be sure to check on them every hour or so to make sure there is still enough liquid to cover the peanuts. Add more water if necessary.

After about 7 hours, the peanuts should be super tender on the inside. Taste for seasoning, and adjust to your liking. 

Serve them right away. Once the boiled peanuts have cooled down, store the leftovers in an airtight container in the refrigerator. They can be eaten cold, or warm them up in a pot over medium heat, or in the microwave for one minute.