To prepare the lemons, quarter them but do not cut all the way. Keep the lemon attached at the base. Open each lemon and sprinkle a generous amount of salt inside.
Place 2 tablespoons of salt in the bottom of a 1 quart mason jar. Pack the lemons in the jar tightly until jar is filled almost to the neck, then fill with lemon juice. Make sure that all of the lemons are completely covered with the juice. Add a couple more tablespoons of salt.
Place the lid on the jar and let sit at room temperature for a couple weeks, checking daily. Put in refrigerator for at least another 2 weeks, until lemon rinds soften.
Store in refrigerator for up to 6 months.
Variation: You can add spices to the lemons for preserving - cloves, coriander seeds, peppercorns, cinnamon stick, or bay leaf.