Sterilize a 1-quart canning jar by immersing it in boiling water for 10 minutes Set aside, using tongs.
Cut the lemons in quarters from the flower tip to within 1/4 inch of the stem end.
Tightly pack the lemons into the jar.
In a medium saucepan, bring the water to a boil and stir in the salt until dissolved.
Fill the jar completely with the salt water and cover tightly.
Let sit at room temperature for 24 hours.
If the water is not up to the brim of the jar, add lemon juice to make up the difference.
Refrigerate for 2 weeks before using.