Wash the peanuts well to make sure all the dirt is dislodged. I usually fill the sink, dump the peanuts in and agitate them.
Place the peanuts in a very large pot and add water to cover the peanuts by 1 inch or more.
Add salt and stir well. Remember that a huge amount of the salt gets discarded with the cooking brine.
Bring it all to a boil, then reduce the heat to a simmer, cover and cook until done. Start testing for doneness after about 4 hours. The peanuts should have a soft, but not mushy, texture. Cook longer if needed. Sometimes it takes 6 or more hours for the peanuts to cook.
After the peanuts are done, drain the brine and store the peanuts in the refrigerator. Don’t let them sit in the brine as they'll become too salty.