Boil 8-10 cups of water so it’s sterile. (This should be enough to cover the garlic bulbs/cloves, plus extra for refreshing the solution.) Add the salt and taste the brine; it shouldn’t be as salty as seawater, just a little salty. Set the brine aside and let cool to room temperature before using.
Peel the outer layers of paper from the garlic, then separate each clove and set them aside. (If using whole bulbs, remove the outermost skins, leaving only 2 layers. Slice off the root and stem ends.)
Soak the cloves (or whole bulbs) in the room-temperature salt water. They should be fully covered in the brine, and you should have additional brine leftover. Cover the bowl loosely and let it sit in a cool, dark place for 2 nights. If using plastic wrap to cover the bowl, poke some holes in the top for airflow. Refresh the soaking liquid with more of the sterile salt water at least 1–2 times during this time, to add more salt as it is absorbed into the cloves.
After 2 nights, pour off all the salt brine. Rinse the garlic, and set it aside to dry completely on a rack or elevated strainer. Any moisture that remains can spoil your pickles, so make sure to let everything dry thoroughly. (If using whole bulbs, dry them on a rack with the stem side down.)