Clean the outsides of 4-6 lemons, rinse and pat dry. Slice the ends from the lemons to create a flat top and bottom. Stand the lemons on one of the flat ends. Cut an "x" into each lemon and stop when you are about ½ inch from cutting all the way through. Open each lemon and pour in ½ tablespoon of salt. Don't worry if some of the salt spills out. Once you salt the lemons, pack them into the jar as tightly as possible. You can use a pestle or a wooden spoon to push them in. Once all of the lemons are in the jar, add an additional 1 tablespoon of salt. Press on the lemons one more time to extract as much juice as possible. If the lemons are submerged in juice you can secure the lid, if not you may need to add additional fresh lemon juice to top them off.
Use a pestle to press on the lemons and extract as much juice as possible. Top off the jar with fresh lemon juice if needed. Seal the jar and store the lemons in a cool dry place for at least 1 week. Give them a shake every once in a while to disperse the juice and salt. After 1 week, move your lemons to refrigerator. When the peels become translucent, you will know they are soft and ready for use. When you are ready to use a lemon, remove it from the jar and rinse to remove excess salt. Cut all of the remaining lemon flesh and pith away from the rind and discard. Chop the preserved lemon peel according to your recipe, or whichever way you prefer. You can store preserved lemons in your refrigerator for up to 6 months