Pick through and rinse beans.
Dissolve 3 tablespoons of salt in 4 quarts of water in a large container.
Add the beans and let soak for at least 8 hours or up to 24 hours.
(To quick-soak: Start with boiling water instead of cold and let the beans soak at room temperature for 1 hour.)
Adjust the oven rack to the lower-middle position and heat the oven to 275 degrees.
Drain and rinse the beans and transfer them to a Dutch oven along with 4 quarts of water and 1 teaspoon of salt.
Bring to a boil over high heat, cover, and transfer to the oven until the beans are Tender, 40 to 60 minutes.